Update CI to work with setup-ruby

[vsppedro]

Saving this link for future references: #1397

[technicalpickles]

What is this referring to exactly? It seems to be using setup-ruby, but is there something specific from that issue?

[vsppedro]

Oh, sorry, my bad. It should be Update CI to work with bundler-cache.

Take a look at this PR: #1467, it tries to close this issue.