As a quality engineer, I want the podman/buildah/skopeo container image build workflow tested in PR-level CI in the new repo (RUN-2021), so that I know changes are unlikely to break anything.

Ref. design doc: https://docs.google.com/document/d/1BSjeZLk18-B5gR9RvHtA5Dpn64q90vJyxWsjwnun-aI/edit?usp=sharing

SPIKE Ref: RUN-1925