Bump black from 25.1.0 to 26.3.1

Bumps [black](https://github.com/psf/black) from 25.1.0 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@25.1.0...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-fmt.txt

@@ -1,6 +1,6 @@
 # Generated from Meta's internal pyfmt requirements
 # Keep these versions in sync with external CI configuration
-black==25.1.0
+black==26.3.1
 stdlibs==2024.1.28
 ufmt==2.8.0
 usort==1.0.8.post1