docs: fix demo URL

README.md

@@ -56,7 +56,7 @@ import ReactPlayer from 'react-player/lazy'
 <ReactPlayer url='https://www.youtube.com/watch?v=ysz5S6PUM-U' />
 ```
 
-Demo page: [`https://cookpete.com/react-player`](https://cookpete.com/react-player)
+Demo page: [`https://cookpete.github.io/react-player`](https://cookpete.github.io/react-player)
 
 The component parses a URL and loads in the appropriate markup and external SDKs to play media from [various sources](#supported-media). [Props](#props) can be passed in to control playback and react to events such as buffering or media ending. See [the demo source](https://github.com/cookpete/react-player/blob/master/src/demo/App.js) for a full example.