Add Python 3.12+/3.13 support and SWIG4 compatibility
To be able for astro to support python >= 3.12, htm has to support python >= 3.12 as well.
The gitlab.astro-wise.org vm has been migrated to the new virtual host. On Friday, 2026-07-24 13:00-16:00, gitlab will not be available, because gitlab and the operating system will be updated.
To be able for astro to support python >= 3.12, htm has to support python >= 3.12 as well.