Update dependency gitlab-org/container-registry to v4.21.0-gitlab

See merge request !2350



Merged-by: Andrew Patterson <apatterson@gitlab.com>
Approved-by: SAhmed <sahmed@gitlab.com>
Approved-by: João Alexandre Cunha <j.a.cunha@gmail.com>
Approved-by: João Pereira <jpereira@gitlab.com>
Approved-by: Andrew Patterson <apatterson@gitlab.com>
Co-authored-by: GitLab Renovate Bot <gitlab-bot@gitlab.com>