Update License badge link

Author: hamchapman

README.md

@@ -5,7 +5,7 @@
 [![Platform](https://img.shields.io/cocoapods/p/PusherSwift.svg?style=flat)](http://cocoadocs.org/docsets/PusherSwift)
 [![Carthage Compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage)
 [![Twitter](https://img.shields.io/badge/[email protected]?style=flat)](http://twitter.com/Pusher)
-[![License MIT](https://go-shields.herokuapp.com/license-MIT-blue.png)](https://opensource.org/licenses/MIT)
+[![GitHub license](https://img.shields.io/badge/license-MIT-lightgrey.svg)](https://raw.githubusercontent.com/pusher-community/pusher-websocket-swift/master/LICENSE.md)
 
 
 ## Table of Contents