It no longer releases, not touches protected remote branches, so no
really need for confirmation.

So we can create a release PR to the stable branch.

The `rubygems:push` task is defined as a prerequisite to the `release`
task as well. And since it's defined earlier, it seems to be run prior
to the other prerequisites.

That is not what we want here. We want every prerequisite satisfied
_before_ actually pushing the gem.

The only thing that really makes the gem available through rubygems is
the actual release tag. Everything else should be a prerequisite to that
in my opinion.