Bump opencv-python-headless from 4.2.0.32 to 4.8.1.78

Bumps [opencv-python-headless](https://github.com/opencv/opencv-python) from 4.2.0.32 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-python-headless
  dependency-type: direct:production
...

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

Author: dependabot[bot]

old_requirements.txt

@@ -1,4 +1,4 @@
 numpy==1.22.0
-opencv-python-headless==4.2.0.32
+opencv-python-headless==4.8.1.78
 scikit-image==0.15.0
 scipy==1.10.0