Publish Operator 0.13.4

Summary

This issue will serve as a checklist and record of releases for GitLab Operator 0.13.4.

Much of the process is automated by release-tools.

To do

1. Confirm that stable branch and tag exist in all mirrors of the project:
   • Canonical repo
   • Security mirror
   • Build mirror
2. Confirm that publish jobs in the tag pipeline in Canonical repo has completed.
3. Confirm that the release is created in the releases page with the associated manifest artifacts.
4. Confirm that the tagged image is pushed to the container registry.
5. Release to OperatorHub.io.
6. Release to OpenShift OperatorHub.io
7. Submit OLM bundle for OpenShift certification