Update sphinx from 7.2.6 to 8.1.0

{{cookiecutter.project_slug}}/requirements_dev.txt

@@ -4,7 +4,7 @@ wheel==0.33.6
 watchdog==0.9.0
 tox==3.14.0
 coverage==4.5.4
-Sphinx==7.2.6
+Sphinx==8.1.0
 twine==5.0.0
 ruff==0.3.5
 {% if cookiecutter.command_line_interface|lower == 'click' -%}