Bump black from 26.1.0 to 26.3.1

Bumps [black](https://github.com/psf/black) from 26.1.0 to 26.3.1.
- [Release notes](https://github.com/psf/black/releases)
- [Changelog](https://github.com/psf/black/blob/main/CHANGES.md)
- [Commits](psf/black@26.1.0...26.3.1)

---
updated-dependencies:
- dependency-name: black
  dependency-version: 26.3.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,7 +1,7 @@
 aniso8601==10.0.1
 async-timeout==5.0.1
 attrs==25.4.0
-black==26.1.0
+black==26.3.1
 blinker==1.9.0
 cachelib==0.13.0
 certifi==2026.1.4