Errors with WMR

Build:

```console
$ npm run build

> build
> wmr build --prerender

Error when using sourcemap for reporting an error: Can't resolve original location of error.

'Provider' is not exported by npm/unistore@3.5.2/preact.js, imported by public/index.js
at si (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:88033)
at Ia.error (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:171300)
at Ia.traceVariable (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:179030)
at Ho.findVariable (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:157247)
at En.findVariable (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:43076)
at Bn.findVariable (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:43076)
at Kn.bind (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:63816)
at Go.bind (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:44364)
at Fo.bind (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:44378)
at Fo.bind (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:155881)
```

In dev (excerpt):

```console
Error bundling unistore/preact.js.map: Error: Unexpected token (Note that you need plugins to import files that are not JavaScript)
at si (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:88033)
at Ia.error (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:171300)
at Ia.tryParse (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:179404)
at Ia.setSource (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:176750)
at uu.addModuleSource (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:328734)
at async uu.fetchModule (/home/jazg/work/micro/beercounter/node_modules/wmr/wmr.cjs:2:329907)
at async Promise.all (index 0) {
code: 'PARSE_ERROR',
parserError: SyntaxError: Unexpected token (1:10)
```

It seems incompatible with WMR (or vice-versa).