- [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? Upload组件 增加maxCount属性 控制最大上传数量 ### What does the proposed API look like? Upload组件 增加maxCount属性 控制最大上传数量 antd 4.17已经有了,请保持同步 目前andv的做法是虽然提供了类似做法,但没有将处理方法内置。如果将处理方法内置,提供了属性控制最大上传数量这样做可能会更好点 <!-- generated by issue-helper. DO NOT REMOVE -->