gRPC migration update

Change-Id: Icdd1a824948fa994cd36bd121c962f5ecf74e3cf
diff --git a/vendor/google.golang.org/grpc/version.go b/vendor/google.golang.org/grpc/version.go
index 483ef89..40af096 100644
--- a/vendor/google.golang.org/grpc/version.go
+++ b/vendor/google.golang.org/grpc/version.go
@@ -19,4 +19,4 @@
 package grpc
 
 // Version is the current grpc version.
-const Version = "1.24.0"
+const Version = "1.25.1"