Add PHPunit 11 support

[Gummibeer]

There were 10 PHPUnit test runner warnings:

1) Class Country cannot be found in /home/runner/work/laravel-translatable/laravel-translatable/tests/Eloquent/Country.php

2) Class CountryStrict cannot be found in /home/runner/work/laravel-translatable/laravel-translatable/tests/Eloquent/CountryStrict.php

3) Class CountryTranslation cannot be found in /home/runner/work/laravel-translatable/laravel-translatable/tests/Eloquent/CountryTranslation.php

4) Class Person cannot be found in /home/runner/work/laravel-translatable/laravel-translatable/tests/Eloquent/Person.php

5) Class PersonTranslation cannot be found in /home/runner/work/laravel-translatable/laravel-translatable/tests/Eloquent/PersonTranslation.php

6) Class StrictTranslation cannot be found in /home/runner/work/laravel-translatable/laravel-translatable/tests/Eloquent/StrictTranslation.php

7) Class Vegetable cannot be found in /home/runner/work/laravel-translatable/laravel-translatable/tests/Eloquent/Vegetable.php

8) Class VegetableTranslation cannot be found in /home/runner/work/laravel-translatable/laravel-translatable/tests/Eloquent/VegetableTranslation.php

9) Class Astrotomic\Translatable\Tests\TestCase declared in /home/runner/work/laravel-translatable/laravel-translatable/tests/TestCase.php is abstract

10) No filter is configured, code coverage will not be processed

--

There was 1 PHPUnit test runner deprecation:

1) Your XML configuration validates against a deprecated schema. Migrate your XML configuration using "--migrate-configuration"!

WARNINGS!