VOL-2630 Release voltha-go 2.3.0

Change-Id: I29ce1ef75c21563a757145faf6cdd16f10fc34f2
diff --git a/VERSION b/VERSION
index d64a644..276cbf9 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.3.0-dev
+2.3.0