Feature Request: migrate from gym to gymnasium

[elliottower]

Hi, would it be possible for offworld-gym to be upgraded from gym to gymnasium? Gymnasium is the maintained version of openai gym and is compatible with current RL training libraries (rllib and tianshou have already migrated, and stable-baselines3 will soon).

This repository is currently listed in the gymnasium third party environments but we are cleaning the list up to only include maintained gymnasium-compatible repositories.

For information about upgrading and compatibility, see migration guide and gym compatibility.