Feature Request: update from gym to gymnasium

[Elliot Tower]

Hi, 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.

Would it be possible for it 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).

For information about upgrading and compatibility, see migration guide and gym compatibility. The main difference is the API has switched to returning truncated and terminated, rather than done, in order to give more information and mitigate edge case issues.

[Alex]

@AminHP: #86 (update from gym to gymnasium)

I have followed some guidelines as in the example:
https://gymnasium.farama.org/tutorials/gymnasium_basics/environment_creation/

[Joao Cunha]

@Alex2782
Great work !

[Mohammad Amin Haghpanah]

I just released version v2.0.0 which is fully compatible with the latest gymnasium.