Upgrade python voltha-protos and pyvoltha in requirements.txt

Change-Id: I4abf7e94cc6b2a7d5480a974f10982b5c5e69af4
diff --git a/python/requirements.txt b/python/requirements.txt
index 9a87401..345bc3b 100644
--- a/python/requirements.txt
+++ b/python/requirements.txt
@@ -64,5 +64,5 @@
 pexpect==4.6.0
 python-consul==0.6.2
 afkak==3.0.0.dev20181106
-pyvoltha==0.1.7
-voltha-protos==0.1.0
+pyvoltha==0.1.8
+voltha-protos==0.1.2