Bump opencv-python from 3.4.2.17 to 4.2.0.32

Bumps [opencv-python](https://github.com/skvark/opencv-python) from 3.4.2.17 to 4.2.0.32.
- [Release notes](https://github.com/skvark/opencv-python/releases)
- [Commits](https://github.com/skvark/opencv-python/commits)

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

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

requirements.txt

@@ -23,7 +23,7 @@ matplotlib==3.0.1
 networkx==2.2
 numpy==1.14.5
 opencv-contrib-python==3.4.3.18
-opencv-python==3.4.2.17
+opencv-python==4.2.0.32
 pafy==0.5.4
 pandas==0.23.4
 Pillow==5.2.0