The `contrib/hello` directory is needed for some CI tests here and in
buildah. Further, the build job that produces images from this
directory are currently broken. Disable the build job, and updte
the README.md to point people at the replacement repo. for this content.
Ref: https://github.com/containers/podman/pull/19730
Signed-off-by: Chris Evich <cevich@redhat.com>