v1.3.1 - preview initialisation fixes

What's Changed

• Update nightly.yml by @zerolab in #15
• Fix for MathJax Preview Initialization Issue by @MadScrewdriver in #17

Full Changelog: 1.3.0...1.3.1

v1.3 - Wagtail 5.2+

This release

• Updates project tooling:
  • added linting with ruff
  • switched to using flit for packaging
  • added GitHub Actions, including PyPI trusted publishing
  • added tests skeleton
• Adds support for Wagtail 5.2+
• Drops support for Wagtail < 5.2, Django < 4.2

And paves the way for the merge with https://github.com/ongchi/wagtail-katex

v1.2 - Wagtail 2 / Django 3 compat

Upgrade to Django 3 / Wagtail 2. Thanks to @zelenij