Installation of dependencies in v1.22

There are some issues depending on the Python version and PyMuPDF and OpenCV

If you are at Python <= 3.5:

$ sudo env/bin/pip install pymupdf==1.16.18

If you experience issues during the installation on Python 3.6:

$ sudo env/bin/pip install opencv-python==3.4.13.47

In case of ImportError: libGL.so.1: cannot open shared object file: No such file or directory

You are missing some dependencies. Run

$ sudo apt update && sudo apt install ffmpeg libsm6 libxext6