New `gitlab:workhorse:install` rake task ## Why was this MR needed? Because with this we can remove the "Ensure the gitlab-workhorse version in Install gitlab-workhorse matches the required version." step from https://gitlab.com/gitlab-org/release-tools/blob/master/doc/release-candidates.md#creating-rc1! MR is ready: gitlab-org/release-tools!57 Closes #22719 See merge request !6574