* Rails and Ruby versions follow the most recent to oldest, except for
Rails main, so we can keep the Gemfile the first one.
* Excluding specific matrix combinations based on the Gemfile first,
Ruby version next, and keep the same order (most recent -> oldest)
* Quote all Ruby versions to keep things consistent. It's required for
the '3.0' version to avoid the float issue where it'd use the latest
3.x instead.
* Test Rails 6.1 with Ruby 3.1, as Rails test suite supports it.
Also update Changelog with the 3.1 Ruby support addition.
I18nCache caused some issues upgrading to Ruby 3, and at the end of the
day I think it's more complexity to keep it around for a marginal gain.
I18n lookups can be expensive, yes, but for most this isn't going to be
a performance hit, and for those where it might be, consider looking at
I18n caching alternatives that aren't specific to these few places where
we had this caching, but to lookups across the board.
Closes#1721Closes#1720
Carlos Antonio da Silva