Support PNPM workspace

Hi there,

We are using pnpm for our monorepo. Some of our dependencies are listed like so (in package.json):

```json
{
"devDependencies": {
"@foo/config": "workspace:*",
},
}
```

You can find the documentation on pnpm workspace: https://www.pnpm.cn/workspaces

Unfortunately, this has caused the following error message when we run auto shipit:

Will auto support pnpm soon enough so we can leverage this great feature?

Thanks