Bump black from 25.1.0 to 25.9.0 in /utf64/py

Bumps [black](https://github.com/psf/black) from 25.1.0 to 25.9.0.
- [Release notes](https://github.com/psf/black/releases)
- [Changelog](https://github.com/psf/black/blob/main/CHANGES.md)
- [Commits](psf/black@25.1.0...25.9.0)

---
updated-dependencies:
- dependency-name: black
  dependency-version: 25.9.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

utf64/py/dev_requirements.txt

@@ -1,2 +1,2 @@
-black==25.1.0
+black==25.9.0
 flit==3.12.0