Add license type: Apache2+PSFL are NOTICE licenses am: 99135410f5 am: fbc97b3d62 am: 2f897bc814

Change-Id: I54798a77818c4a509d7a921168b565de2aca1660
diff --git a/METADATA b/METADATA
index 2ed3777..7dfdf9b 100644
--- a/METADATA
+++ b/METADATA
@@ -12,5 +12,6 @@
     value: "https://github.com/agronholm/pythonfutures"
   }
   version: "3.2.0"
+  license_type: NOTICE
   last_upgrade_date { year: 2018 month: 1 day: 4 }
 }