gRPC migration

Change-Id: I3129ae27d7ee12a23c7046f0d877e8064f2fd7f4
diff --git a/vendor/github.com/opentracing/opentracing-go/go.mod b/vendor/github.com/opentracing/opentracing-go/go.mod
new file mode 100644
index 0000000..bf48bb5
--- /dev/null
+++ b/vendor/github.com/opentracing/opentracing-go/go.mod
@@ -0,0 +1,5 @@
+module github.com/opentracing/opentracing-go
+
+go 1.14
+
+require github.com/stretchr/testify v1.3.0