Remove support for Python 3.8

[lorenzodb1]

• Please check if the PR fulfills these requirements

• [x] Tests for the changes have been added

• [x] Docs have been added / updated

• [x] All CI checks are green

• What kind of change does this PR introduce?

This PR removes support for Python 3.8, for it's nearing its EOL according to Status of Python versions.

• Other information:

N.B. THIS PR SHOULD BE PUSHED ONLY AFTER OCTOBER 2024