Dep update and update python requirements.txt

dep update protos to current tagged version.
No functional change.

Update requirements.txt to pip released versions
of voltha-protos and pyvoltha.

Also doc update to reflect golang 1.12 install and
combined Makefile

Change-Id: I455cc84ab4ead7aa26f49c3d35227f5d8a360808
diff --git a/vendor/github.com/opencord/voltha-protos/VERSION b/vendor/github.com/opencord/voltha-protos/VERSION
index 7a8795e..b1e80bb 100644
--- a/vendor/github.com/opencord/voltha-protos/VERSION
+++ b/vendor/github.com/opencord/voltha-protos/VERSION
@@ -1 +1 @@
-0.1.3-dev
+0.1.3