Tag version 2.0.0

Also use new versions of pyvoltha and voltha-protos

Change-Id: I4bbbfa7278b1f50ba16950d93229bf7787f89f58
diff --git a/VERSION b/VERSION
index c0ab82c..227cea2 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.0.1-dev
+2.0.0