Bump opencv-python from 4.7.0.72 to 4.8.1.78 (#1274)

Bumps [opencv-python](https://github.com/opencv/opencv-python) from 4.7.0.72 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: indirect
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>