tox: add Python 3.14 ends

[woodruffw]

This is atop #261; will rebase when that's merged (or this could be merged into it first).

Signed-off-by: William Woodruff william@yossarian.net

[di]

Looks like the are some changes to the way urllib handles filepath parsing in 3.14 that are causing failures here. Specifically, this check is failing:

pip-api/pip_api/_vendor/packaging/requirements.py

Lines 112 to 113 in 2cdc76f

	if urllib.parse.urlunparse(parsed_url) != req.url:
	raise InvalidRequirement("Invalid URL given")

Looks like this check was removed in pypa/packaging@fe8f0bb

We probably need to land #196 or a later update to the vendored packaging library to get tests passing again.