Revert the removal of buildah dependency

We currently need it to drag in recent versions of other dependencies,
per https://github.com/containers/skopeo/issues/796 .

I'll work to update the relevant dependencies in c/image, but that will
only propagate to skopeo in the next c/image release; in the meantime,
this at least undoes the downgrades.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

vendor/github.com/docker/distribution/registry.go

@@ -54,6 +54,11 @@ type RepositoryEnumerator interface {
 	Enumerate(ctx context.Context, ingester func(string) error) error
 }
 
+// RepositoryRemover removes given repository
+type RepositoryRemover interface {
+	Remove(ctx context.Context, name reference.Named) error
+}
+
 // ManifestServiceOption is a function argument for Manifest Service methods
 type ManifestServiceOption interface {
 	Apply(ManifestService) error
@@ -73,6 +78,21 @@ func (o WithTagOption) Apply(m ManifestService) error {
 	return nil
 }
 
+// WithManifestMediaTypes lists the media types the client wishes
+// the server to provide.
+func WithManifestMediaTypes(mediaTypes []string) ManifestServiceOption {
+	return WithManifestMediaTypesOption{mediaTypes}
+}
+
+// WithManifestMediaTypesOption holds a list of accepted media types
+type WithManifestMediaTypesOption struct{ MediaTypes []string }
+
+// Apply conforms to the ManifestServiceOption interface
+func (o WithManifestMediaTypesOption) Apply(m ManifestService) error {
+	// no implementation
+	return nil
+}
+
 // Repository is a named collection of manifests and layers.
 type Repository interface {
 	// Named returns the name of the repository.