VOL-5135 - Create a beta branch for voltha-openolt-adapter

VERSION
-------
  o Bump version string with suffix *-dev for post release versioning.

Change-Id: Ib794f3869705d5363f22709f900140da5ac03085
diff --git a/VERSION b/VERSION
index 48c3ccc..ca27416 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.3.7-dev
+4.3.9-dev