Bump platformdirs from 4.5.0 to 4.5.1 in /docs

Bumps [platformdirs](https://github.com/tox-dev/platformdirs) from 4.5.0 to 4.5.1.
- [Release notes](https://github.com/tox-dev/platformdirs/releases)
- [Changelog](https://github.com/tox-dev/platformdirs/blob/main/CHANGES.rst)
- [Commits](tox-dev/platformdirs@4.5.0...4.5.1)

---
updated-dependencies:
- dependency-name: platformdirs
  dependency-version: 4.5.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

docs/requirements.txt

@@ -28,7 +28,7 @@ msgpack==1.1.2
 myst-parser==4.0.1
 natsort==8.4.0
 packaging==25.0
-platformdirs==4.5.0
+platformdirs==4.5.1
 Pygments==2.19.2
 PyYAML==6.0.3
 requests==2.32.5