Add back ObsDict and ActionDict

[pimpale]

Description

Adds back ObsDict and ActionDict to the pettingzoo.utils.env module.

Fixes Farama-Foundation/Shimmy#106 .

Type of change

• Bug fix (non-breaking change which fixes an issue)

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

[pimpale]

Question: how can we mark a constant as deprecated? Stack Overflow has some solutions, but they seem a bit heavyweight.

[elliottower]

Question: how can we mark a constant as deprecated? Stack Overflow has some solutions, but they seem a bit heavyweight.

Honestly don't think we need to deprecate it, they're fine for people to use and could make things simpler for new users, we just happen to not use them internally anymore for this repo (but on shimmy I'll probably just leave it as is)

[elliottower]

It's giving TypeError: 'type' object is not subscriptable in CI btw, not sure exactly how to fix that or what the difference is between what was there previously

[pimpale]

The issue was using dict instead of typing.Dict.

[RedTachyon]

@elliottower Shouldn't this be pushed in a hotfix release asap? At the moment this completely breaks all multiagent stuff in shimmy unless you manually downgrade PZ

[elliottower]

Yeah that's the plan sorry I've just not had a chance to write up release notes