Consider caching gems to make the gitlab-rails-ce job faster and more resilient when Rubygems has problems
Rubygems seems to currently have problems, which leads to problems in our CI pipelines (e.g. https://gitlab.com/gitlab-org/build/CNG-mirror/-/jobs/207740638).
If we'd cache the vendor/ruby
folder, similarly to how we do for the CE/EE pipelines we would make the jobs faster and more resilient to Rubygems issues.