doc: Update README.md

Author: jaywcjlove

core/README.md

@@ -1,6 +1,11 @@
 Layout
 ===
 
+[![NPM Downloads](https://img.shields.io/npm/dm/@uiw/react-layout.svg?style=flat)](https://www.npmjs.com/package/@uiw/react-layout)
+[![Build & Deploy](https://github.com/uiwjs/react-layout/actions/workflows/ci.yml/badge.svg)](https://github.com/uiwjs/react-layout/actions/workflows/ci.yml)
+[![Open in unpkg](https://img.shields.io/badge/Open%20in-unpkg-blue)](https://uiwjs.github.io/npm-unpkg/#/pkg/@uiw/react-layout/file/README.md)
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+
 Handling the overall layout of a page.
 
 > ⚠️ Note: Implemented with flex layout, please pay attention to [browser compatibility](http://caniuse.com/#search=flex) issues.