ci(pr): use oras push rather than oras cp since it does not accept files

Author: mac641

.github/workflows/pr.yaml

@@ -113,7 +113,9 @@ jobs:
     - name: Push OCI image
       run: |
         docker buildx bake --no-cache --set _common.output+=type=oci,dest=./debian-oci.tar debian
-        oras cp --from-oci-layout ./debian-oci.tar ghcr.io/metal-stack/debian-oci:${SEMVER_MAJOR_MINOR}${SEMVER_PATCH}
+        # TODO: login to ghcr using oras
+        oras push ghcr.io/metal-stack/debian-oci:${SEMVER_MAJOR_MINOR}${SEMVER_PATCH} ./debian-oci.tar
+        # oras cp --from-oci-layout ./debian-oci.tar ghcr.io/metal-stack/debian-oci:${SEMVER_MAJOR_MINOR}${SEMVER_PATCH}
       env:
         CIS_VERSION: v4.1-4
         IMG_PKG_COMMAND: dpkg -l