VOL-5088
v2.12 - update voltha.protos version in all go.mod configs

Change-Id: I6228ad6f1fd521fd3d54218e8dd137a2e6d5016e
diff --git a/VERSION b/VERSION
index 871e300..cd57a8b 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.1.5-dev
+2.1.5