Tag pyvoltha release 0.1.8

Change-Id: Iae576e0b8b08d66e65ca3d4526b1696525ac468a
diff --git a/VERSION b/VERSION
index 2c6f178..699c6c6 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.1.7dev0
\ No newline at end of file
+0.1.8