Add Python 3.13 support

[fafanoulele]

Add support for Python 3.13.

Current error with Python 3.13:

httptools/parser/url_parser.c:5746:70: error: too few arguments to function call, expected 6, have 5
       5744 |                 int ret = _PyLong_AsByteArray((PyLongObject *)v,
            |                           ~~~~~~~~~~~~~~~~~~~
       5745 |                                               bytes, sizeof(val),
       5746 |                                               is_little, !is_unsigned);

[jameshilliard]

Maybe also add a 3.13 wheel build here and tests here?

[fafanoulele]

Maybe also add a 3.13 wheel build here and tests here?

Done. Thanks for the feedback!

[fantix]

Merged in #107, thanks for the PR!