Use Ruby 2.6.5 CI images
Related to https://gitlab.com/gitlab-org/omnibus-gitlab/issues/4658. Depends on gitlab-build-images!261 (merged).
Edited by Balasankar 'Balu' C
Related to https://gitlab.com/gitlab-org/omnibus-gitlab/issues/4658. Depends on gitlab-build-images!261 (merged).