Is your feature request related to a problem? Please describe.

The current versions of setup-renv and friends utilize GitHub cache, which is great, but is incompatible with local testing environments such as act. This makes local workflow iteration challenging.

Describe the solution you'd like

An option to disable the cache step completely as opposed to simply cache invalidation.

Describe alternatives you've considered

Forking the action. ;)

Additional context

ACT sets an environment variable (ACT) to TRUE when running locally. This is one generally recommended way of having skipping GitHub-specific steps for local testing.