Voltha 2.6 release notes

Change-Id: Ibdc7904581eca8e8777de380d919b94d3613fcff
diff --git a/VERSION b/VERSION
index 8f87ff7..e70b452 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.6.0-dev
+2.6.0