Using voltha-lib-go 4.0.2

Change-Id: Ic5bb6913d52ce49ac46f4ecdb811fa1d1fb3581a
diff --git a/go.mod b/go.mod
index 8c21d44..bb4a98b 100644
--- a/go.mod
+++ b/go.mod
@@ -7,7 +7,7 @@
 	github.com/gogo/protobuf v1.3.1
 	github.com/golang/protobuf v1.3.2
 	github.com/grpc-ecosystem/go-grpc-middleware v1.0.1-0.20190118093823-f849b5445de4
-	github.com/opencord/voltha-lib-go/v4 v4.0.1
+	github.com/opencord/voltha-lib-go/v4 v4.0.2
 	github.com/opencord/voltha-protos/v4 v4.0.2
 	go.etcd.io/etcd v0.0.0-20190930204107-236ac2a90522
 	google.golang.org/grpc v1.25.1