Remove *-dev from version string to publish content onto docs.voltha.org

Change-Id: I61a31da7b51fe24dc6550fffeded56c603ceddc2
diff --git a/VERSION b/VERSION
index 20e4310..d8b6989 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.12.0-dev2
+2.12.0