Remove support for old python versions

[packi]

Debian just dropped 3.10 in their latest release.

[codecov]

Codecov Report

Merging #595 (57a9350) into main (6dce5bf) will decrease coverage by 0.11%.
The diff coverage is n/a.

❗ Current head 57a9350 differs from pull request most recent head bf5e852. Consider uploading reports for the commit bf5e852 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #595      +/-   ##
==========================================
- Coverage   91.31%   91.20%   -0.11%     
==========================================
  Files          32       32              
  Lines        4684     4684              
==========================================
- Hits         4277     4272       -5     
- Misses        407      412       +5     

see 2 files with indirect coverage changes

[rdunklau]

Is it really necessary to drop old versions ? A lot of users may be using older distros, as long as it doesn't cost us too much it would be nice to keep pghoard working for them.

[giacomo-alzetta-aiven]

Dropping python3.7 is fine since it is EOLed (recent rohmu versions have dropped support as well), but I wouldn't just drop 3.8-3.10 without any particular reason.