Login with dependency proxy

See merge request gitlab-org/build/CNG!573

Explicitly wait on the PID instead of a pgrep search

See merge request gitlab-org/build/CNG!539

Check branch name for ubi8 pipelines

See merge request gitlab-org/build/CNG!546

We should consider triggering the UBI build-related jobs when the branch
name matches '-ubi8$'. Otherwise, the user has to manually trigger a
pipeline with `UBI_PIPELINE=true` every time.

Use --queue-selector flag for Sidekiq

See merge request gitlab-org/build/CNG!548

Default to non-root user for ubi certificates container

Closes gitlab-org/charts/gitlab#2369

See merge request gitlab-org/build/CNG!538

ubi8: Enable jemalloc by default

See merge request gitlab-org/build/CNG!550

We enabled jemalloc by default for the standard images in
https://gitlab.com/gitlab-org/build/CNG/-/merge_requests/543. Now we do
the same with the UBI8 images.

Include a copy of the openssh client binaries

See merge request gitlab-org/build/CNG!549

Clean up the artifacts at the end of the job

See merge request gitlab-org/build/CNG!542

Update the use of Bundler.clean_exec in our rails dependencies helper

See merge request gitlab-org/build/CNG!547