Bump opencv-contrib-python from 4.2.0.34 to 4.8.1.78 in /variations

Bumps [opencv-contrib-python](https://github.com/opencv/opencv-python) from 4.2.0.34 to 4.8.1.78.
- [Release notes](https://github.com/opencv/opencv-python/releases)
- [Commits](https://github.com/opencv/opencv-python/commits)

---
updated-dependencies:
- dependency-name: opencv-contrib-python
  dependency-type: direct:production
...

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

variations/requirements.txt

@@ -1,5 +1,5 @@
 absl-py==0.9.0
 opencv-python==4.2.0.34
-opencv-contrib-python==4.2.0.34
+opencv-contrib-python==4.8.1.78
 Pillow==10.3.0
 tesserocr==2.4.0