Fix darwin-pkg

Author: provokateurin

cmd/packaging/darwin-pkg.go

@@ -22,7 +22,7 @@ var DarwinPkgTask = &packagingTask{
 	packagingFunction: func(tmpPath, applicationName, packageName, executableName, version, release string) (string, error) {
 		outputFileName := fmt.Sprintf("%s %s.pkg", applicationName, version)
 
-		payload, err := os.OpenFile(filepath.Join("flat", "base.pkg", "Payload"), os.O_RDWR|os.O_CREATE, 0755)
+		payload, err := os.OpenFile(filepath.Join(tmpPath, "flat", "base.pkg", "Payload"), os.O_RDWR|os.O_CREATE, 0755)
 		if err != nil {
 			return "", err
 		}