It should be managed in rubygems/rubygems and sync-ed to ruby/ruby. We
shouldn't get PRs to rubygems in ruby/ruby.

  directory value may be not support glob files from subdirectories

  This reverts commit ad3db6711c4aa48c82f4091342aab7394ee45736.

  Above commit break dependabot update since Nov, 2023.

While `directory: "/"` is defaulted to ".github/workflows", we need to
update the files under ".github/actions".

* Automerge for dependabot update

* change update period with daily, we can merge it automatically when `make check` of Ubuntu was passed

* Use rebase instead of merge commit

* check all Ubuntu jobs

It's not that important for ruby/ruby to keep them up to date.

It seems like dependabot supports updating the `# vX.Y.Z` comment.
The reason why I disabled this was that it failed to update this, but
maybe it was because it had `, checking sha`. Let me try it again with
that removed.

because you have to manually update the version tag comment.
It feels unsafe to trust third party git tags when you need to pass
MATZBOT_GITHUB_TOKEN to it. Git commit sha alone isn't human-readable
and I'm reluctant to remove the comment either. It doesn't seem worth
the effort to review changes for every release of this action.