Bump sphinx from 8.1.3 to 8.2.1

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 8.1.3 to 8.2.1.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/v8.2.1/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v8.1.3...v8.2.1)

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

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

requirements/checkdocs.txt

@@ -60,11 +60,13 @@ pyproject-hooks==1.0.0
     #   pip-tools
 requests==2.32.0
     # via sphinx
+roman-numerals-py==3.1.0
+    # via sphinx
 sniffio==1.3.1
     # via anyio
 snowballstemmer==2.2.0
     # via sphinx
-sphinx==8.1.3
+sphinx==8.2.1
     # via
     #   -r requirements/checkdocs.in
     #   sphinx-autobuild

requirements/docs.txt

@@ -60,11 +60,13 @@ pyproject-hooks==1.0.0
     #   pip-tools
 requests==2.32.0
     # via sphinx
+roman-numerals-py==3.1.0
+    # via sphinx
 sniffio==1.3.1
     # via anyio
 snowballstemmer==2.2.0
     # via sphinx
-sphinx==8.1.3
+sphinx==8.2.1
     # via
     #   -r requirements/docs.in
     #   sphinx-autobuild