Downgrader

[spaze]

I'd like to write modern PHP (8.3+), and use ondrejmirtes/simple-downgrader to downgrade the code to 7.2, commit to a release branch and release the package from that branch.

Here's what I have:

1. Downgrade the code with vendor/bin/simple-downgrade downgrade --configuration=build/downgrade.php 7.2
2. Update composer.json with build/downgrade-composer.php

Missing:

1. Once the code has been downgraded, commit to a release branch, create a tag
2. Run all tests in GitHub against the release branch, run only the tests targeting "modern" PHP against the dev branch