Umi: [Feature Request] 单页应用切换路由，提供返回顶部的功能

[LeezQ]

Background

单页应用切换路由的时候，需要回到页面顶部

Proposal

提供相关的配置项，比如 scrollTop: true

[sorrycc]

react-router 推荐的做法是在路由组件生命周期里写 window.scrollTo(0, 0)

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.