releasing voltha-bbsim 2.0

Change-Id: I2db4517fc090d56fd47a530cd8303503c9abac4a
diff --git a/VERSION b/VERSION
index 0d4d124..227cea2 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.1.0-dev
+2.0.0