Update dependencies pre release

vendor/github.com/golang/protobuf/proto/clone.go

@@ -84,15 +84,9 @@ func mergeStruct(out, in reflect.Value) {
 		mergeAny(out.Field(i), in.Field(i), false, sprop.Prop[i])
 	}
 
-	if emIn, ok := extendable(in.Addr().Interface()); ok {
-		emOut, _ := extendable(out.Addr().Interface())
-		mIn, muIn := emIn.extensionsRead()
-		if mIn != nil {
-			mOut := emOut.extensionsWrite()
-			muIn.Lock()
-			mergeExtension(mOut, mIn)
-			muIn.Unlock()
-		}
+	if emIn, ok := in.Addr().Interface().(extendableProto); ok {
+		emOut := out.Addr().Interface().(extendableProto)
+		mergeExtension(emOut.ExtensionMap(), emIn.ExtensionMap())
 	}
 
 	uf := in.FieldByName("XXX_unrecognized")