希望notification加个数量控制或者设置只显示一个的功能

- [ ] 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?
快速点击会弹多个

### What does the proposed API look like?
notification.config({
maxCount: 3,
single: true
});