Assess if any related repositories need to be updated to Ruby 3.1 before we update gitlab rails

According to https://docs.gitlab.com/ee/development/ruby_upgrade.html#decide-which-repositories-to-update

When upgrading Ruby, consider updating the following repositories:

• Gitaly_ (example)_
• GitLab LabKit_ (example)_
• GitLab Exporter_ (example)_
• GitLab Experiment_ (example)_
• Gollum Lib_ (example)_
• GitLab Helm Chart_ (example)_
• GitLab Sidekiq fetcher_ (example)_
• Prometheus Ruby Mmap Client_ (example)_
• GitLab-mail_room_ (example)_

To assess which of these repositories are critical to be updated alongside the main GitLab application consider:

• The Ruby version scope.
• The role that the service or library plays in the overall functioning of GitLab.

Refer to the list of GitLab projects for a complete account of which repositories could be affected. For smaller version upgrades, it can be acceptable to delay updating libraries that are non-essential or where we are certain that the main application test suite would catch regressions under a new Ruby version.

This issue is to carry out that assessment, and create any subsequent required issues/mrs.

Further - we should potentially update the above text, since some of the repo's might not be relevant any more?