Typo in p1 feature array

[lewj85]

The PantheonRL environment wrapper for overcookedgym uses an old version of HumanCompatibleAI's overcooked_ai repo under the hood. Unfortunately, this old version contains a typo in the p1 feature array here: https://github.com/HumanCompatibleAI/overcooked_ai/blob/6eaceb0a9a2501f1b9fccbf4c7016d6662ed1108/overcooked_ai_py/mdp/overcooked_mdp.py#L1157

Instead of
abs_pos_p1 = np.array(p0.position)
it should be
abs_pos_p1 = np.array(p1.position)

This needs to be refactored to wrap a more recent version of that overcooked_ai repo where the feature array typo was fixed. Or this file needs to be corrected after cloning the old repo.