Add support for Laravel 12

[mfn]

Summary

It's this time of the year again to prepare for the next release.

Might still be off some months, but nevertheless the versions are already available and currently resolve to dev-master:

…
  - Downloading laravel/framework (dev-master 9243eac)
  - Downloading orchestra/canvas-core (10.x-dev 4a628d6)
  - Downloading phpunit/phpunit (11.5.6)
…

• Added automated tests
• Documented for all relevant versions
• Updated the changelog

[spawnia]

Thanks!