Update pyoxipng requirement from ~=9.0.0 to ~=9.1.0

Updates the requirements on [pyoxipng](https://github.com/nfrasser/pyoxipng) to permit the latest version.
- [Release notes](https://github.com/nfrasser/pyoxipng/releases)
- [Changelog](https://github.com/nfrasser/pyoxipng/blob/main/CHANGELOG.md)
- [Commits](nfrasser/pyoxipng@v9.0.0...v9.1.0)

---
updated-dependencies:
- dependency-name: pyoxipng
  dependency-type: direct:production
...

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

requirements.txt

@@ -12,7 +12,7 @@ mergedeep~=1.3.4
 mini-racer~=0.12.4
 numpy>=1.22.4
 Pillow~=11.1.0
-pyoxipng~=9.0.0
+pyoxipng~=9.1.0
 python-telegram-bot~=21.9
 psutil~=6.1.1
 PyMemoryEditor~=1.5.22