SlimeVolley initial ball velocity is incorrect

[lowrollr]

Small issue with game state initialization:

evojax/evojax/task/slimevolley.py

Lines 794 to 798 in 67c90e1

	def get_random_ball_v(key: jnp.ndarray):
	result = random.uniform(key, shape=(2,)) * 2 - 1
	ball_vx = result[1]*20
	ball_vy = result[2]*7.5+17.5
	return ball_vx, ball_vy

result[2] is out of bounds, which means it accesses the same value as result[1] -- and therefore ball_vx and ball_vy depend on the same value. This means the ball has higher y-vel when x-vel is positive, so the ball will be thrown higher to one player compared to the other.