v0.6 - Wagtail 4.1+ and internal 📦 tidy ups

This release makes Wagtail 4.1+ only support official.

It also moves to using ruff under the hood

What's Changed

• Support wagtail 4.2 by @nickmoreton in #44
• Update tox and CI testing by @nickmoreton in #46

New Contributors

• @nickmoreton made their first contribution in #44

Full Changelog: v0.5.0...v0.6.0