Consider adding spotless and error prone to github actions

[jkiddo]

Should we consider adding spotless and/or errorprone to the github actions?

[joofio]

Can you explain what that means?

[jkiddo]

Spotless: https://github.com/diffplug/spotless Errorproine: https://github.com/google/error-prone

[joofio]

github action or precommit hook? (or both?)

[dotasek]

HAPI itself uses spotless checks both as action and pre-commit, so adopting that seems entirely appropriate.

Actually, I haven't seen a spotless complaint from my HAPI git command line lately. Only checkstyle failures in the PR checks. I think I will go check if spotless is working for pre-commits...

I'll bring up error prone with some of the dev team. It's present in the codebase, but doesn't seem to be actively checked by anything.