message: docs: add custom nav config
diff: @@ -64,6 +64,13 @@ export default {
  '/zh-CN/docs': getMenus('zh-CN'),
  '/docs': getMenus(),
  },
  + navs: [
  + null,
  + {
  + title: 'v2.x',
  + path: 'https://v2.umijs.org',
  + },
  + ],
  },
  exportStatic: {},
  };
  