refactor: use metav1.ObjectMeta in other types

pkg/api/serialization_test.go

@@ -356,7 +356,7 @@ func roundTrip(t *testing.T, codec runtime.Codec, item runtime.Object) {
 func TestEncodePtr(t *testing.T) {
 	grace := int64(30)
 	pod := &api.Pod{
-		ObjectMeta: api.ObjectMeta{
+		ObjectMeta: metav1.ObjectMeta{
 			Labels: map[string]string{"name": "foo"},
 		},
 		Spec: api.PodSpec{