drop support of very old Python versions

[12rambau]

I'm moving my CI from 3.9 to 3.11 and it becomes more and more diffcult to maintain something compatible with stuff that are as old as Python 2. According to Python official documentation 2.7has reached end-of life 5 years ago and was the last v2.

In my opinion none of the tools that are relying on 2.something will require a patch from you as they basically cannot update any major lib anymore (numpy, pandas, pills, matplotlib etc....) What would be the problem of making the lib embrace more modern coding pattern (like type hinting) ?

People using 2.7 will still be able to use deprecated, pip will just relsolve their latest version available to 1.2.15 which seems fair to me.

On my side mypy is crashing on deprecated starting from 3.11 (it was working fine on 3.10).