Bump black from 25.11.0 to 25.12.0 in /requirements

Bumps [black](https://github.com/psf/black) from 25.11.0 to 25.12.0.
- [Release notes](https://github.com/psf/black/releases)
- [Changelog](https://github.com/psf/black/blob/main/CHANGES.md)
- [Commits](https://github.com/psf/black/compare/25.11.0...25.12.0)

---
updated-dependencies:
- dependency-name: black
  dependency-version: 25.12.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

requirements/dev.txt

@@ -9,7 +9,7 @@ requests-mock==1.12.1
 pytest-mock==3.15.1
 
 # Lint and code style
-black==25.11.0
+black==25.12.0
 flake8-blind-except==0.2.1
 flake8-debugger==4.1.2
 flake8-docstrings==1.7.0