Tag version 2.0.0

Also use new versions of pyvoltha and voltha-protos

Change-Id: I840b36093b7d4954d875bdcb7877e8bb521d6a2c
diff --git a/VERSION b/VERSION
index c0ab82c..227cea2 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.0.1-dev
+2.0.0