VOL-2030 Release master branch voltha-api-server version 2.2.0

Change-Id: Ib02bc8745b74aa78367b7794c91d0f9892caa423
diff --git a/VERSION b/VERSION
index 97ade15..ccbccc3 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.2.0-dev
+2.2.0