Stop using docker.Image
Stop using docker.Image

Instead, use DockerReference() to obtain the repository name (which
also makes it work for other transports that support Docker references),
and a check for docker.Transport + docker.GetRepositoryTags.

This will allow dropping docker.Image from containers/image, and maybe
even all of ImageReference.NewImage (forcing callers to think about
manifest lists, among other things).

projectatomic/skopeo,projectatomic/skopeo,mtrmac/skopeo,mtrmac/skopeo,mtrmac/skopeo