Update soupsieve to 2.6

[pyup-bot]

This PR updates soupsieve from 2.5 to 2.6.

Changelog

2.6

-   **NEW**: Add official support for Python 3.13.
-   **NEW**: Add support for `&` as scoping root per the CSS Nesting Module, Level 1. When `&` is used outside the
 context of nesting, it is treated as the scoping root (equivalent to `:scope`).
-   **FIX**: Improve error message when an unrecognized pseudo-class is used.

Links

• PyPI: https://pypi.org/project/soupsieve
• Changelog: https://data.safetycli.com/changelogs/soupsieve/