Update pillow requirement from <12,>=11 to >=11,<13 in /workers

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@11.0.0...12.1.1)

---
updated-dependencies:
- dependency-name: pillow
  dependency-version: 12.1.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

workers/requirements.txt

@@ -1,4 +1,4 @@
 httpx>=0.28,<1
 open-clip-torch>=2.26,<3
-Pillow>=11,<12
+Pillow>=11,<13
 pytest>=8.4,<9