chore(deps): Bump sphinx from 7.4.7 to 8.1.3

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.4.7 to 8.1.3.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](https://github.com/sphinx-doc/sphinx/compare/v7.4.7...v8.1.3)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -17,7 +17,7 @@ requests==2.32.3
 rst2pdf==0.102
 smartypants==2.0.1
 snowballstemmer==2.2.0
-Sphinx==7.4.7
+Sphinx==8.1.3
 sphinx-copybutton==0.5.2
 sphinx-rtd-theme==2.0.0
 sphinx-rtd-dark-mode==1.3.0