[VOL-4293] OpenONU Adapter update for gRPC migration

Change-Id: I05300d3b95b878f44576a99a05f53f52fdc0cda1
diff --git a/vendor/golang.org/x/sys/unix/syscall_darwin.1_12.go b/vendor/golang.org/x/sys/unix/syscall_darwin.1_12.go
index b31ef03..b009860 100644
--- a/vendor/golang.org/x/sys/unix/syscall_darwin.1_12.go
+++ b/vendor/golang.org/x/sys/unix/syscall_darwin.1_12.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 darwin && go1.12 && !go1.13
 // +build darwin,go1.12,!go1.13
 
 package unix