PHP 8.4 support

[sboden]

When using DrupalDriver in a Drupal 10/11 with PHP 8.4 it generates warnings about nullable parameters.

I'll add a local generated patch. Nullable ('?') parameters are supported since PHP 7.1

drupal-driver-php84-nullable-params.patch

[sboden]

I needed the above patch to get DrupalDriver v2.3 working without warnings, but the master branch already seems to have it fixed.