Drop python 2 support & dependency on "future" due to CVE-2025-50817

[johncarter-phntm]

This package is flagged by security warnings due to this vulnerability in future

• CVE-2025-50817 PythonCharmers/python-future#650
• https://nvd.nist.gov/vuln/detail/CVE-2025-50817

It would be good to drop support for older pythons (e.g. <3.9), and remove this dependency.

[johncarter-phntm]

It does look like that was planned ( #618 (comment) ), but I think the package currently isn't maintained.

[johncarter-phntm]

See also

• Dependency on future #784
• Remove dependency on future #795