Add Pusher's Beam Api (public-apis#791)

* Add Pusher's Beam Api

* Update formatting of Pusher Beam

Author: NaveenDA

README.md

@@ -244,6 +244,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Plino](https://plino.herokuapp.com/) | Spam filtering system | No | Yes | Unknown |
 | [ProxyCrawl](https://proxycrawl.com) | Scraping and crawling anticaptcha service | `apiKey` | Yes | Unknown |
 | [Public APIs](https://github.com/davemachado/public-api) | A collective list of free JSON APIs for use in web development | No | Yes | Unknown |
+| [Pusher Beams](https://pusher.com/beams) | Push notifications for Android & iOS | `apiKey` | Yes | Unknown |
 | [QR code](http://qrtag.net/api/) | Create an easy to read QR code and URL shortener | No | Yes | Yes |
 | [QR code](http://goqr.me/api/) | Generate and decode / read QR code graphics | No | Yes | Unknown |
 | [ReqRes](https://reqres.in/ ) | A hosted REST-API ready to respond to your AJAX requests | No | Yes | Unknown |