I didn't change the Lint job, since it gave me weird issues in CI, not
locally, with gems not in this project showing up as being required, and
not existing.
After years of providing an awesome service for free, which we are very
grateful for, TravisCI will be dropping their free plan on Dec 31. So,
we are switching to GHA.
Drops multi-db (foo/bar) tests. Managing three databases per RDBMS
was turning into a huge hassle, and they needed to be rewritten anyway for
rails 6, per Eileen's talk.