title: use free texture packer for phaser3
body: <p>I'm using phaser3 and free texture packer, is it possible to do that? if yes please tell me how?
  I tried to use <code>addAtlasJSONHash</code> but it was logging that this function is undefined, so I tried <code>game.addAtlasJSONHash</code>, but the same error was happening</p>