Bump opencv-python in /harmoni_detectors/harmoni_face_detect

Bumps [opencv-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-python
  dependency-type: direct:production
...

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

harmoni_detectors/harmoni_face_detect/requirements.txt

@@ -1,4 +1,4 @@
-opencv-python==4.2.0.34
+opencv-python==4.8.1.78
 dlib==19.18.0
 imutils==0.5.3