VOL-2030 Release master branch voltha-openolt-adapter version 2.2.0

Change-Id: I0eef632bab79f85b84ab351ff0a735838a7db2fc
diff --git a/VERSION b/VERSION
index 97ade15..ccbccc3 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.2.0-dev
+2.2.0