Do not support end-of-life Python releases

3 years 1/2 ago, our goal was to support Python 3.4 #59, that was then an active Python release.

Now even Python 3.6 is end-of-life, released more than 5 years ago and with no security fixes, and without any official Docker image #50

We could stick to provide support for active releases of Python, that would mean anything released in the 5 last years.