Updates README.md to added react-router-ext (#320)

Updates README.md to added react-router-ext Built with Microbundle

README.md

@@ -117,6 +117,7 @@ Here's what's coming up for Microbundle:
 - [brazilian-utils](https://github.com/brazilian-utils/brazilian-utils) Utils library for specific Brazilian businesses.
 - [react-hooks-lib](https://github.com/beizhedenglong/react-hooks-lib) A set of reusable react hooks.
 - [mdx-deck-live-code](https://github.com/JReinhold/mdx-deck-live-code) A library for [mdx-deck](https://github.com/jxnblk/mdx-deck) to do live React and JS coding directly in slides.
+- [react-router-ext](https://github.com/ri7nz/react-router-ext) An Extended [react-router-dom](https://github.com/ReactTraining/react-router/tree/master/packages/react-router-dom) with simple usage.
 
 ## 🥂 License