Drop support for python 3.8, declare support for 3.13

[youtux]

🤔 What's changed?

• Dropped support for python 3.8, which is now EOL
• Declared support for 3.13, which is now stable
• Update the codebase to remove constructs for python < 3.9

⚡️ What's your motivation?

Keeping the codebase updated.

🏷️ What kind of change is this?

• 🏦 Refactoring/debt/DX (improvement to code design, tooling, etc. without changing behaviour)
• 💥 Breaking change (incompatible changes to the API)

♻️ Anything particular you want feedback on?

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct
• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• Users should know about my change
  • I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

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[jsa34]

Should we add pyupgrade to the pre-commit yml?

[youtux]

Should we add pyupgrade to the pre-commit yml?

Yes, and possibly flake8 too, so that we can see unused imports.
I'll do that in a next PR