docs: readme updates, next-video callout (#1751)

* docs: remove polyfills section, outdated

* docs: add next-video callout

Author: luwes

README.md

@@ -12,6 +12,10 @@
   A React component for playing a variety of URLs, including file paths, YouTube, Facebook, Twitch, SoundCloud, Streamable, Vimeo, Wistia, Mixcloud, DailyMotion and Kaltura. Not using React? <a href='#standalone-player'>No problem.</a>
 </p>
 
+---
+
+> Using Next.js and need to handle video upload/processing? Check out [next-video](https://github.com/muxinc/next-video).
+
 ### ✨ The future of ReactPlayer
 
 Maintenance of ReactPlayer is being taken over by [Mux](https://www.mux.com). The team at Mux have worked on many highly respected projects and are committed to improving video tooling for developers.
@@ -58,11 +62,6 @@ The component parses a URL and loads in the appropriate markup and external SDKs
 
 For platforms without direct use of `npm` modules, a minified version of `ReactPlayer` is located in `dist` after installing. To generate this file yourself, checkout the repo and run `npm run build:dist`.
 
-#### Polyfills
-
-* If you are using `npm` and need to support [browsers without `Promise`](http://caniuse.com/#feat=promises) you will need a [`Promise` polyfill](https://github.com/stefanpenner/es6-promise).
-* To support IE11 you will need to use [`babel-polyfill`](https://babeljs.io/docs/usage/polyfill) or a similar ES2015+ polyfill.
-
 #### Autoplay
 
 As of Chrome 66, [videos must be `muted` in order to play automatically](https://www.theverge.com/2018/3/22/17150870/google-chrome-autoplay-videos-sound-mute-update). Some players, like Facebook, cannot be unmuted until the user interacts with the video, so you may want to enable `controls` to allow users to unmute videos themselves. Please set `muted={true}`.