remotes/docker: add scope (registry:foo/bar:pull)

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

remotes/docker/fetcher.go

@@ -31,6 +31,11 @@ func (r dockerFetcher) Fetch(ctx context.Context, desc ocispec.Descriptor) (io.R
 		return nil, err
 	}
 
+	ctx, err = contextWithRepositoryScope(ctx, r.refspec, false)
+	if err != nil {
+		return nil, err
+	}
+
 	for _, path := range paths {
 		u := r.url(path)