Add compatibility for Python 3.6

With some work and dependencies pinned to version compatible with Python 3.6 we can make it work.

importlib_metadata==4.8.3
zipp==3.6.0
typing-extensions==4.0.1
rich==10.16.0
Pygments==2.11.0

The reason for this MR is that OpenSUSE Leap is still using Python 3.6 😞