When using `yarn link`, wmr cache needs to be removed after package rebuilds

[rschristian]

Describe the bug When using yarn link (and presumably npm link too) the cache WMR keeps means that when the package is rebuilt, the user is not using the up-to-date version, but the old cached version. The cache will have to be manually cleared by the user.

To Reproduce

1. Link a package
2. Start WMR to generate a .cache directory
3. Rebuild the linked package with some alteration
4. Restart dev server
5. See old version of package still in .cache

Expected behavior After a dev server restart I'd expect the cache to be updated, especially if the package is one that is symlinked and isn't higher up in the directory tree (such as in a monorepo).

Desktop (please complete the following information):

• OS: Arch Linux
• Node Version: 14.16.0
• WMR Version: 1.7.0