V1.4.7之后a-menu-item绑定自定义属性，无法用$attrs对象获取

[tuibian]

• I have searched the issues of this repository and believe that this is not a duplicate.

Version

1.6.1

Environment

OS：Windows。browser：Google Chrome 75。Vue version：2.6.10.

Reproduction link

https://github.com/tuibian/vue-antdesign

Steps to reproduce

1.run server.2.run mock.
浏览器访问localhost:8080,随便用户名密码登录后点击左侧菜单选项

What is expected?

右侧tab展示点击的菜单页面

What is actually happening?

控制台报错

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.