Update importlib.metadata typings for 3.10

[itaisteinherz]

Fixes #7262
Refs #6557

// cc @Molkree @hauntsaninja

[itaisteinherz]

At first I thought that I'll need to add EntryPoints as well, but after another look it seems like it isn't used by any public method.

[itaisteinherz]

At first I thought that I'll need to add EntryPoints as well, but after another look it seems like it isn't used by any public method.

It seems like EntryPoints will be required for the typing of SelectableGroups.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[srittau]

Just one more thing I noticed, looks good to me otherwise.

[itaisteinherz]

@AlexWaygood should I have also added SelectableGroups and EntryPoints to __all__? I just noticed your PR #7326, which initially added __all__, and noticed I forgot to add them.
(I also noticed that you didn't include EntryPoint in __all__?)

[AlexWaygood]

@AlexWaygood should I have also added SelectableGroups and EntryPoints to __all__? I just noticed your PR #7326, which initially added __all__, and noticed I forgot to add them. (I also noticed that you didn't include EntryPoint in __all__?)

@itaisteinherz, none of them are included in __all__ at runtime, so I don't see any reason to include them in __all__ in the stub :) https://github.com/python/cpython/blob/2c228a7b8f89e9ed8d390370abd771d4993b79d8/Lib/importlib/metadata/__init__.py#L30