VOL-2030 Release 2.1 branch voltha-openonu-adapter version 2.1.1

Change-Id: Iede127e57224a42e445f8e5be9fdf7fe9c07aacd
diff --git a/VERSION b/VERSION
index 7c7e096..3e3c2f1 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.1.1-dev
+2.1.1