Drop support for Python 3.8

[cpburnz]

Before support for Python 3.8 can be dropped, the following dependent packages need to drop support first:

• hatchling: latest version (v1.27.0 from 2024-12-15) still supports Python 3.8.
  • See pyproject.toml.

[cpburnz]

Hatchling removed Python 3.8 support in commit 79d3c15 from 2025-09-27. Python 3.8 will be dropped in the next release.