[VOL-2570]Make skew configurable for performance metrics

Change-Id: I68f9cf537bd46b27f5ac188a3de9d512e60c1a46
diff --git a/python/requirements.txt b/python/requirements.txt
index e90a615..a1db739 100644
--- a/python/requirements.txt
+++ b/python/requirements.txt
@@ -1,2 +1,2 @@
-voltha-protos==3.3.9
-pyvoltha==2.4.7
+voltha-protos==3.4.0
+pyvoltha==2.5.1