ggcr: from scratch images created using obsolete application/vnd.docker.distribution.manifest.v2+json mediaType

### Describe the bug

`empty.Image` is creating an empty container image with the obsolete mediaType `application/vnd.docker.distribution.manifest.v2+json`

### To Reproduce

See related issue https://github.com/GoogleContainerTools/kaniko/issues/3319

### Expected behavior

Empty container images are created with current expected mediaType `application/vnd.oci.image.manifest.v1+json`.

### Additional context

As a consequence of this bug, Kaniko images built from scratch get the obsolete mediaType `application/vnd.docker.distribution.manifest.v2+json` and get rejected by OCI-only container registries (like ZOT).
As mentioned above, the related Kaniko issue related issue https://github.com/GoogleContainerTools/kaniko/issues/3319 gives much more context information.

I have been looking for the moment when Docker switch their default format from their legacy one to the current OCI one, but I could not find it. It is in any case not a very recent change.