build(deps-dev): bump sphinx from 7.4.7 to 8.1.3 (#674)

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/v8.1.3/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v7.4.7...v8.1.3)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-version: 8.1.3
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

poetry.lock

@@ -43,7 +43,7 @@ pre-commit = "^4.0.1"
 optional = true
 
 [tool.poetry.group.docs.dependencies]
-sphinx = ">=7.1,<8.0.0"
+sphinx = ">=7.1,<9.0.0"
 sphinx-rtd-theme = ">=3.0.2,<4.0.0"
 sphinx-autodoc-typehints = ">=2.3.0,<3.0.0"
 docutils = ">=0.21.2,<1.0.0"