- [x] I have searched the [issues](https://github.com/vueComponent/ant-design-vue/issues) of this repository and believe that this is not a duplicate. ### What problem does this feature solve? 关于模态框(modal)可以增加上下左右等8个方法的大小伸缩 ### What does the proposed API look like? 关于模态框(modal)可以增加上下左右等8个方法的大小伸缩  <!-- generated by issue-helper. DO NOT REMOVE -->