This method will set a new size for your game.
It should only be used if you're looking to change the base size of your game and are using
one of the Scale Manager scaling modes, i.e.
FIT. If you're using
NONE and wish to
change the game and canvas size directly, then please use the
resize method instead.
The new width of the game.
The new height of the game.
The Scale Manager instance.