feat: add tests folder with phpstan level 8 solved all errors #156

Job	Run time
check	14s
PHP-CS-Fixer	9s
Twig-CS-Fixer	15s
PHP 8.4 tests (No Symfony specified)	15s
PHP 8.2 tests (No Symfony specified)	18s
PHP 8.1 tests (Lowest deps)	13s
PHP 8.5 tests (No Symfony specified)	14s
PHP 8.1 tests (No Symfony specified)	18s
PHP 8.4 tests (Dev deps)	16s
PHP 8.3 tests (No Symfony specified)	16s
PHPStan	18s
PHP 8.1 tests (Symfony 6)	13s
	2m 59s

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