Start new dev version

Change-Id: I7c6e0337c24fa4c4f4fdb9b64fe62665629700e8
diff --git a/VERSION b/VERSION
index 276cbf9..32d1656 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.3.0
+2.3.1-dev