Add a third party environment: Box Jump

[zzbuzzard]

Description

Hi! I've just finished documenting and releasing Box Jump, a custom PettingZoo environment I made recently which aims to be a simple co-op environment that can scale to many agents. This pull request simply adds it to the third party environment list.

Type of change

• This change requires a documentation update

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have run pytest -v and no errors are present.
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I solved any possible warnings that pytest -v has generated that are related to my code to the best of my knowledge.
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[zzbuzzard]

Hi @David-GERARD, please could you have a look at this?

[David-GERARD]

@zzbuzzard we're on it!

[David-GERARD]

@zzbuzzard Thanks for contributing!

[zzbuzzard]

Great thanks :)