Bump supported Python versions

[s-heppner]

Python 3.12, 3.13, and 3.14 are the current stable and actively supported versions.
We should discuss when to bump our supported versions.

Edit 2026-08-11 Dev-Team-Meeting:

We decided on the following:

• min_version gets bumped, when it becomes EoL or we need a feature of the newer version.
• max_version gets bumped when a new stable version releases and the CI runs clean on this version (both pr.yaml and main.yaml).

[s-heppner]

Based on our need for Python 3.11 and its built-in toml library, and the fact that Python 3.10 reaches EoL in 2 months, we decided to bump the min_version to Python 3.11 and the max_version to the newest stable version Python 3.14.