Tree组件，expandedKeys只能使用数组赋值，不能push进去

[since2006]

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

Version

1.1.7

Environment

Chrome 70.0.3538.77, Vue 2.5.17

Reproduction link

Steps to reproduce

打开重现链接即可看到效果，具体查看 App.vue

What is expected?

expandedKeys.push('key') 也能展开节点

What is actually happening?

无法展开

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[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.