Enable cache action for lint workflow (#84026)
Cache all python dependencies using [GHA cache](https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows). I'm doing this for lint workflow first and will slowly roll it out to other workflows.
### Testing
Before caching, pip cache is not found. Dependencies installation continues as usual:
After caching https://github.com/pytorch/pytorch/runs/8006214772?check_suite_focus=true. The long hash at the end of the cache key is the hash of requirements files
Note that the cache is in the runners themselves. This should be a transparent process.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/84026
Approved by: https://github.com/seemethere, https://github.com/suo, https://github.com/malfet
