Vulnerabilities on version 4.0.0 with PostCSS

Hi, when updating dependencies I got a message about 34 moderate severity vulnerabilities. These are apparently caused by the outdated version of PostCSS. Here is the full `npm audit` output:

```
# npm audit report

postcss 7.0.0 - 8.2.9
Severity: moderate
Regular Expression Denial of Service - https://npmjs.com/advisories/1693
fix available via `npm audit fix --force`
Will install rollup-plugin-postcss@1.6.3, which is a breaking change
node_modules/cssnano-util-raw-cache/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/css-declaration-sorter/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/cssnano-preset-default/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/cssnano/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-calc/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-colormin/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-convert-values/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-discard-comments/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-discard-duplicates/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-discard-empty/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-discard-overridden/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-merge-longhand/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-merge-rules/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-minify-font-values/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-minify-gradients/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-minify-params/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-minify-selectors/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-charset/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-display-values/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-positions/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-repeat-style/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-string/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-timing-functions/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-unicode/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-url/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-whitespace/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-ordered-values/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-reduce-initial/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-reduce-transforms/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-svgo/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-unique-selectors/node_modules/postcss
node_modules/rollup-plugin-postcss/node_modules/stylehacks/node_modules/postcss
css-declaration-sorter 4.0.0 - 5.1.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/css-declaration-sorter
cssnano-preset-default <=4.0.0-rc.2 || 4.0.1 - 4.0.8
Depends on vulnerable versions of css-declaration-sorter
Depends on vulnerable versions of cssnano-util-raw-cache
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/cssnano-preset-default
cssnano 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.1.1 - 4.1.11
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/cssnano
rollup-plugin-postcss >=2.0.0
Depends on vulnerable versions of cssnano
node_modules/rollup-plugin-postcss
cssnano-util-raw-cache >=4.0.1
Depends on vulnerable versions of postcss
node_modules/cssnano-util-raw-cache
postcss-calc 6.0.2 - 7.0.5
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-calc
postcss-colormin 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2 - 4.0.3
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-colormin
postcss-convert-values 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-convert-values
postcss-discard-comments 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-discard-comments
postcss-discard-duplicates 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-discard-duplicates
postcss-discard-empty 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-discard-empty
postcss-discard-overridden 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-discard-overridden
postcss-merge-longhand 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.6 - 4.0.11
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-merge-longhand
postcss-merge-rules 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2 - 4.0.3
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-merge-rules
postcss-minify-font-values 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-minify-font-values
postcss-minify-gradients 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-minify-gradients
postcss-minify-params 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-minify-params
postcss-minify-selectors 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-minify-selectors
postcss-normalize-charset 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-charset
postcss-normalize-display-values <=4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-display-values
postcss-normalize-positions <=4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-positions
postcss-normalize-repeat-style <=4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-repeat-style
postcss-normalize-string <=4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-string
postcss-normalize-timing-functions <=4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-timing-functions
postcss-normalize-unicode <=4.0.0-rc.2 || 4.0.1
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-unicode
postcss-normalize-url 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-url
postcss-normalize-whitespace <=4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-normalize-whitespace
postcss-ordered-values 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.1.1 - 4.1.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-ordered-values
postcss-reduce-initial 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2 - 4.0.3
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-reduce-initial
postcss-reduce-transforms 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-reduce-transforms
postcss-svgo 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.3
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-svgo
postcss-unique-selectors 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/postcss-unique-selectors
stylehacks 4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.3
Depends on vulnerable versions of postcss
node_modules/rollup-plugin-postcss/node_modules/stylehacks

34 moderate severity vulnerabilities

To address issues that do not require attention, run:
npm audit fix

To address all issues (including breaking changes), run:
npm audit fix --force
```

Is there a way to fix this?