Add license type: Apache2 is a NOTICE license am: 39de3b544a

Change-Id: Id6285b24f68cd59e5e0c4e8d33e79c7be86df791
diff --git a/METADATA b/METADATA
index 9c9b51c..536369d 100644
--- a/METADATA
+++ b/METADATA
@@ -10,6 +10,7 @@
     value: "https://github.com/google/apitools"
   }
   version: "v0.5.30"
+  license_type: NOTICE
   last_upgrade_date {
     year: 2019
     month: 6