pip prod(deps): update pillow requirement

Updates the requirements on [pillow](https://github.com/python-pillow/Pillow) to permit the latest version.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst)
- [Commits](python-pillow/Pillow@11.1.0...12.1.0)

---
updated-dependencies:
- dependency-name: pillow
  dependency-version: 12.1.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements-optional.txt

@@ -1,5 +1,5 @@
 matplotlib<3.10.9
-pillow>11,<12.0.1
+pillow>11,<12.1.1
 pyrevolve==2.2.7
 scipy<1.15.4
 distributed<2025.11.1