PHP 8.4 deprecation warnings

[rxu]

Since PHP 8.4 implicitly nullable parameter declarations has been deprecated, so there's a couple of deprecation warnings thrown on DBUnit while using on PHP 8.4:

PHPUnit\DbUnit\Database\DefaultConnection::createDataSet(): Implicitly marking parameter $tableNames as nullable is deprecated, the explicit nullable type must be used instead

PHPUnit\DbUnit\Database\DataSet::buildTableSelect(): Implicitly marking parameter $databaseConnection as nullable is deprecated, the explicit nullable type must be used instead

So, for PHP 8.4 those parameters need to be typehinted as array|null and Connection|null respectively.
Thanks for supporting DBUnit :)

EDIT: okay, union type is not possible for PHP 7.4. So, there should be another fix probably.