Add Drupal 10 support

This is troublesome...by supporting ^9 || ^10, I need to inject logic into my upgrade path test because the core fixture was changed. :-(

Let's see how the test bot likes....THIS.

The only non-test changes were return type declarations. Return type declarations have been supported since php 7.0.0.

I don't see any reason to delay.

Automatically closed - issue fixed for 2 weeks with no activity.