Bump pydantic from 2.8.2 to 2.9.1 (#356)

Bumps [pydantic](https://github.com/pydantic/pydantic) from 2.8.2 to 2.9.1.
- [Release notes](https://github.com/pydantic/pydantic/releases)
- [Changelog](https://github.com/pydantic/pydantic/blob/main/HISTORY.md)
- [Commits](pydantic/pydantic@v2.8.2...v2.9.1)

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

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

docs/requirements.txt

@@ -2,7 +2,7 @@
 recommonmark==0.7.1
 sphinx==7.4.7; python_version >= '3.9'
 sphinx-rtd-theme==2.0.0; python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4, 3.5'
-pydantic==2.8.2
+pydantic==2.9.1
 pyqt5==5.15.11
 appdirs==1.4.4
 python-dateutil==2.9.0.post0