Update sphinx requirement from >=6.0 to >=8.1.3

[dependabot]

Updates the requirements on sphinx to permit the latest version.

Release notes

Sourced from sphinx's releases.

Sphinx 8.1.3

Changelog: https://www.sphinx-doc.org/en/master/changes/8.1.html

Bugs fixed

• #13013: Restore support for cut_lines() with no object type. Patch by Adam Turner.

Changelog

Sourced from sphinx's changelog.

Release 8.1.3 (released Oct 13, 2024)

Bugs fixed

• #13013: Restore support for :func:!cut_lines with no object type. Patch by Adam Turner.

Release 8.1.2 (released Oct 12, 2024)

Bugs fixed

• #13012: Expose :exc:sphinx.errors.ExtensionError in sphinx.util for backwards compatibility. This will be removed in Sphinx 9, as exposing the exception in sphinx.util was never intentional. :exc:!ExtensionError has been part of sphinx.errors since Sphinx 0.9. Patch by Adam Turner.

Release 8.1.1 (released Oct 11, 2024)

Bugs fixed

• #13006: Use the preferred https://www.cve.org/ URL for the :rst:role::cve: <cve> role. Patch by Hugo van Kemenade.
• #13007: LaTeX: Improve resiliency when the required fontawesome or fontawesome5 packages are not installed. Patch by Jean-François B.

Release 8.1.0 (released Oct 10, 2024)

Dependencies

• #12756: Add lower-bounds to the sphinxcontrib-* dependencies. Patch by Adam Turner.
• #12833: Update the LaTeX parskip package from 2001 to 2018. Patch by Jean-François B.

Incompatible changes

• #12763: Remove unused internal class sphinx.util.Tee.

... (truncated)

Commits

• a1510de Bump to 8.1.3 final
• 62e9606 Restore support for cut_lines() with no object type (#13015)
• 5ae32ce Bump version
• a72b47b Bump to 8.1.2 final
• 39a45ad Expose ExtensionError in sphinx.util for backwards compatibility.
• 5a4859a Add docs about sphinx-autobuild (#13011)
• 05679ef Type-check the 'autodoc_intenum' example (#12827)
• 86d1d31 Prune CHANGES of unneeded sections
• b6269d3 Improve documentation for the Builder API (#13008)
• c46abc4 Improve clarity for master_doc and root_doc
• Additional commits viewable in compare view