VOL-3588 Update OFAgent to support new version of protos

Change-Id: Ic3944779f9a600ebcd5d7a916616f473059e311e
diff --git a/go.mod b/go.mod
index b4e12eb..53b157d 100644
--- a/go.mod
+++ b/go.mod
@@ -3,11 +3,13 @@
 go 1.13
 
 require (
+	github.com/gogo/protobuf v1.3.1 // indirect
 	github.com/golang/protobuf v1.3.2
 	github.com/grpc-ecosystem/go-grpc-middleware v1.0.1-0.20190118093823-f849b5445de4
 	github.com/opencord/goloxi v1.0.1
-	github.com/opencord/voltha-lib-go/v3 v3.2.8
-	github.com/opencord/voltha-protos/v3 v3.4.1
+	github.com/opencord/voltha-lib-go/v4 v4.0.2
+	github.com/opencord/voltha-protos/v4 v4.0.2
+	github.com/opentracing/opentracing-go v1.2.0 // indirect
 	github.com/stretchr/testify v1.4.0
 	golang.org/x/net v0.0.0-20191112182307-2180aed22343
 	google.golang.org/grpc v1.25.1