It seems this has been around since November, although if they announced
it I missed it. Anyway, I'd guess the node12 runner will be going away
soon.

Marking these as major changes since that's what GH did when doing this
to their own actions.

Then adjust the version refs to pull in those major updates to the GH actions.

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/1980287937