[VOL-4290] Voltha go library updates for gRPC migration

Change-Id: I1aa2774beb6b7ed7419bc45aeb53fcae8a8ecda0
diff --git a/vendor/golang.org/x/net/http2/go111.go b/vendor/golang.org/x/net/http2/go111.go
index 3a13101..5bf62b0 100644
--- a/vendor/golang.org/x/net/http2/go111.go
+++ b/vendor/golang.org/x/net/http2/go111.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.11
 // +build go1.11
 
 package http2