build(deps): bump kloppy from 3.14.0 to 3.15.0 in /docs

Bumps [kloppy](https://github.com/PySport/kloppy) from 3.14.0 to 3.15.0.
- [Release notes](https://github.com/PySport/kloppy/releases)
- [Changelog](https://github.com/PySport/kloppy/blob/master/docs/changelog.md)
- [Commits](PySport/kloppy@3.14.0...3.15.0)

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

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

docs/requirements.txt

@@ -1,4 +1,4 @@
 sphinx==8.0.2
 furo==2024.8.6
 sphinx-autodoc-typehints==2.2.3
-kloppy==3.14.0
+kloppy==3.15.0