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

Change-Id: I8bbf2263a7090b73555027cc54ff5c55a66ee4fb
diff --git a/go.mod b/go.mod
index eacb199..f993b57 100644
--- a/go.mod
+++ b/go.mod
@@ -4,9 +4,11 @@
 
 require (
 	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 v3.2.2
 	github.com/opencord/voltha-protos/v3 v3.4.1
+	github.com/opentracing/opentracing-go v1.1.0
 	github.com/stretchr/testify v1.4.0
 	golang.org/x/net v0.0.0-20191112182307-2180aed22343
 	google.golang.org/grpc v1.25.1