code: @TaskAction
    public void stageAction() throws AppEngineException {
      getProject().delete(stageStandardExtension.getStagingDirectory());
      appCfg
          .newStaging(CloudSdkOperations.getDefaultHandler(getLogger()))
          .stageStandard(stageStandardExtension.toStageStandardConfiguration());
    }
docs: Task entrypoint : stage the standard app.