Update phaser github url

phaser has moved to the phaserjs org

Author: andrew

topics/phaser/index.md

@@ -2,7 +2,7 @@
 aliases: phaserjs
 created_by: Richard Davey
 display_name: Phaser
-github_url: https://github.com/photonstorm/phaser
+github_url: https://github.com/phaserjs/phaser
 logo: phaser.png
 short_description: Phaser is a fun, free, and fast 2D game framework for making HTML5 games for desktop and mobile web browsers.
 topic: phaser