[VOL-3196] Enhanced gRPC interfaces to create and propagate Span for log correlation

Change-Id: I48389ca3e8675b64515bfd3088a4de9b688f5cae
diff --git a/go.mod b/go.mod
index 632206d..3fd611a 100644
--- a/go.mod
+++ b/go.mod
@@ -7,8 +7,10 @@
 	github.com/cenkalti/backoff/v3 v3.1.1
 	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/v3 v3.2.3
 	github.com/opencord/voltha-protos/v3 v3.4.1
+	github.com/opentracing/opentracing-go v1.1.0
 	go.etcd.io/etcd v0.0.0-20190930204107-236ac2a90522
 	google.golang.org/grpc v1.25.1
 )