Replace usage of an incompatible function with PHP7.4 with the compatible one

Author: jakubtobiasz

src/Fixer/FinalClassInEntitiesFixer.php

@@ -69,6 +69,6 @@ public function getPriority(): int
 
     public function supports(SplFileInfo $file): bool
     {
-        return str_contains($file->getPath(), 'src/Entity');
+        return strpos($file->getFilename(), 'src/Entity') !== false;
     }
 }