Release 2.1.0 of pyvoltha (same as 0.2.4)

Change-Id: I9b92742ff449ff348f37403466e5f02c1fb6385a
diff --git a/VERSION b/VERSION
index abd4105..7ec1d6d 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.2.4
+2.1.0