Bump minimum required Python version to 3.10

[bbannier]

With python-3.9 only receiving security updates some projects have stopped publishing wheels for new releases, e.g., tree-sitter requires python>=3.10 as of 0.24.0 so we cannot build wheels with that version anymore, see #100.

This PR bumps the minimum required Python version to 3.10. This means that we are incompatible with the Python requirements of e.g., https://github.com/zeek/zeek itself which currently requires python>=3.9. Since zeekscript is not required to operate Zeek this seems acceptable to me, especially given that python-3.9 will hit EOL 2025-10 so the rest of the Zeek ecosystem might bump its minimum requirement too in the nearer future (i.e., somewhere in the 7.2-8.x timeframe).

[bbannier]

@ckreibich @timwoj could you chime in on this? Like I wrote, this seems fine for an optional package.

[timwoj]

I think this is fine. I agree that it's an optional package that doesn't ship with Zeek, so it doesn't necessarily need to follow Zeek's version requirements.