Bump opencv-python-headless from 4.1.0.25 to 4.1.1.26

Bumps [opencv-python-headless](https://github.com/skvark/opencv-python) from 4.1.0.25 to 4.1.1.26.
- [Release notes](https://github.com/skvark/opencv-python/releases)
- [Commits](https://github.com/skvark/opencv-python/commits)

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

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Author: dependabot[bot]

old_requirements.txt

@@ -1,5 +1,5 @@
 numpy==1.16.4
-opencv-python-headless==4.1.0.25
+opencv-python-headless==4.1.1.26
 scikit-image==0.15.0
 scipy==1.3.0
 pandas==0.25.0