Change Champion Upgrade Requirements

Change the requirement for upgrades of champions from 3 to 2, it will significantly speed up the game. This has been tried in another auto battle game called auto chess, and it has been wildly successful in cutting the playtime in half. This will take a 40min game and reduce it to roughly a 20min game. Which is right around the time you should be aiming for.

More importantly you can widen the champion pool, because it takes so many less champions to upgrade you can stuff a good 5-10 extra champions in the rotation.