Fix no_proxy to support IPV6 CIDR format

[p3ck]

Summary

Fixes no_proxy to support IPV6 CIDR format.

no_proxy=fe11::/16 python -c 'import httpx; c = httpx.Client()'

Closes: #3221

Checklist

• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.

[ofilip]

Hi, thanks for this PR. I found this httpx issue 6 months ago and wanted to address it since then. Your change only makes httpx not crash when an IPv6 range is in no_proxy but it is not properly handled. I build upon your work and addressed the issue with extending URLPattern functionality with ip range handling with ipaddress.ip_range.

I did not manage to push or create a PR to your branch so at least I'm sharing the commit: 92067fe

EDIT: PR is here: p3ck#1

It is also not yet properly tested as I didn't manage to run all tests. I only managed to run tests I modified.

[p3ck]

@ofilip Thank you for the great work. Can you check the changes I made to get it to pass linting and testing?

Thanks

[ofilip]

@ofilip Thank you for the great work. Can you check the changes I made to get it to pass linting and testing?

Thanks

I reviewed your commits and everything seems in place. Thx a lot for review, tests and improvements.