Upgrade Ruby to 2.6.3
Ruby 2.6 offers better performance and memory usage: https://www.rubyguides.com/2018/11/ruby-2-6-new-features/
Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/57323
Ruby 2.6 offers better performance and memory usage: https://www.rubyguides.com/2018/11/ruby-2-6-new-features/
Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/57323