Upgrade ruby version to 2.3.5

Open Zeger-Jan van de Weg requested to merge zj/gitlab-ce:zj-ruby-2.3.5 into master

What does this MR do?

Use the ruby 2.3.5 containers

Does this MR meet the acceptance criteria?

part of: gitlab-org/gitlab-ce#38040

Edited by Zeger-Jan van de Weg