Bump opencv-contrib-python from 3.4.3.18 to 4.2.0.32

Bumps [opencv-contrib-python](https://github.com/skvark/opencv-python) from 3.4.3.18 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-contrib-python
  dependency-type: direct:production
...

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requirements.txt

@@ -22,7 +22,7 @@ Markdown==3.0.1
 matplotlib==3.0.1
 networkx==2.2
 numpy==1.14.5
-opencv-contrib-python==3.4.3.18
+opencv-contrib-python==4.2.0.32
 opencv-python==3.4.2.17
 pafy==0.5.4
 pandas==0.23.4