[webencodings] Add stubs

[donbarbos]

PyPI: https://pypi.org/project/webencodings/
Source: https://github.com/gsnedders/python-webencodings
Stats: https://pypistats.org/packages/webencodings

[srittau]

I'm also a bit wary that the last release and the last commit was 2017.

Edit: Also, the project looks to be quite dead: gsnedders/python-webencodings#27

[donbarbos]

Then we can add no_longer_updated field almost immediately after uploading stubs to PyPI

[github-actions]

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

[srittau]

@donbarbos I've forced an upload: https://pypi.org/project/types-webencodings/

[donbarbos]

@srittau It seems that in cases like this, when it's not clear that support has ended, the opposite is assumed.
I had a proposal for a similar case (#13821), but it was not accepted.

In both cases, the authors didn't announce the end of support, at least I didn't find it.