updated for afrouterTest to work with new protos

Change-Id: Ibf1b74e73e3726c6dc83a79d6ff93acc44943103
diff --git a/Gopkg.toml b/Gopkg.toml
index f728695..a3f6ad1 100644
--- a/Gopkg.toml
+++ b/Gopkg.toml
@@ -79,6 +79,10 @@
   name = "github.com/stretchr/testify"
   version = "1.3.0"
 
+[[constraint]]
+  name = "github.com/opencord/voltha-protos"
+  branch = "master"
+
 [[override]]
   name = "go.etcd.io/etcd"
   branch = "master"