Update `.gitlab-ci.yml` templates to use new variables

Description

Our CI templates include references to things like CI_BUILD_REF_NAME that are now deprecated. We should update our own examples to use the new variables.

Proposal

Links / references

• Needed because of https://gitlab.com/gitlab-org/gitlab-ce/issues/29053

@ayufan I marked this as 9.1 since it's kinda silly to use deprecated variables.

Should we move this to https://gitlab.com/gitlab-org/gitlab-ci-yml project?

moved from gitlab-ce#29229

@markpundsack this had been taken care of in 2e2ce5e6 however, this was not included in 9.0 the release process didn't include them. Given this was marked 9.1 this will be done in the release process and this issue can be closed.

closed