pip install pybgs only works up to opencv_version 3.4.7

When installing via `pip install pybgs` building the wheel or running setup.py fails.
The error is always during cmake compilation.
`2020-08-24T14:09:04,468 /tmp/pip-install-l94hfk2g/pybgs/src/algorithms/DPAdaptiveMedian.cpp:24:33: error: no matching function for call to ‘_IplImage::_IplImage(const cv::Mat&)’
`
or very similar.
I played around with various opencv-versions and different ubuntu-versions. I also tried building opencv from source or installing libopencv-dev from apt.
Here are my findings:
On Ubunut 20.04 there is only opencv 4.2 available in apt. When installing opencv via `$sudo apt install libopencv-dev` the pybgs installation via`$pip install pybgs` fails with a similar error as stated above
On Ubuntu 18.04 there is OpenCV 3.2 available in apt:
`$pip install pybgs`
works

When building OpenCV from source it works for opencv_version < 3.4.8. Version 3.4.7. is the latest version where it works.

To reprodruce try the following:
Build and make install opencv > 3.4.7 from sources
`$pip install pybgs --no-cache-dir` will fail. `--no-cache-dir` is required as otherwise the old *.whl will be used.
For opencv 4.x it will also fail but with a slightly different error.
Installing libopencv_dev from apt will work as long as you do not use Ubuntu 20.04. Unfortunatly there is no opencv < 3.4.7 available via apt in Ubuntu 20.04.