types: make everything type check

[Gobot1234]

Summary

Use more 3.7+ features in the library and make everything type check. This also adds support for using the union operator for python 3.10+ for Union/Optional

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
  • This change has an associated test.
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

[Gobot1234]

No idea where this pkg_resources failure came from

[Gobot1234]

@cetanu do you have any idea why the tests are failing?

[cetanu]

Looking now...

[cetanu]

It appears to be related to this

grpc/grpc#33570

but it's just a deprecation warning? I think we can catch this

[cetanu]

https://github.com/grpc/grpc/blob/master/tools/distrib/python/grpcio_tools/grpc_tools/protoc.py#L21

[cetanu]

Since this is only for generating the tests, we could do something very hacky

    import re
    from importlib import resources

    file = resources.files("grpc_tools") / Path("protoc.py")
    content = file.read_text()

    if "import pkg_resources" in content:
        content = re.sub(
            pattern="import pkg_resources",
            repl=r"try:\n    import pkg_resources\nexcept DeprecationWarning:\n    pass",
            string=content,
        )

    file.open().write(content)

[Gobot1234]

I'll just send a PR to fix it

[tzahush]

@Gobot1234 I see the PR that we were waiting for here grpc/grpc#35329 is closed, what should we do as next steps? perhaps this was fixed in different PR's.

[Gobot1234]

Note to self should try and get more places to use positional only params. Also should probably mark survey methods as abstractmethods(?)

[toby-bro]

mypy still does not manage to type check this correctly, it seems related to this missing feature.
That is supposedly corrected by : https://mypy.readthedocs.io/en/stable/runtime_troubles.html#using-classes-that-are-generic-in-stubs-but-not-at-runtime
I might open a PR for this in the future...
EDIT 1 : I realise you passed to pyright but one of the helpfull functionnalities of betterproto is that it is type hinted and when using it in mypy type checked repos then typing is correct, which is not the case anymore