feat: support pnpm workspaces

It would be great if howfat supports [pnpm workspaces](https://pnpm.io/workspaces).

```json
"dependencies": {
  "@example/core": "workspace:*"
},
```

Running howfat local inside a monorepo package using ` "workspace:*"`, currently throws an error.

```sh
Error: Unsupported URL Type "workspace:": workspace:*
```