Remove no longer used annotation use statements and replace with attribute use statements

src/Bundle/ChillActivityBundle/Entity/ActivityPresence.php

@@ -12,7 +12,7 @@ declare(strict_types=1);
 namespace Chill\ActivityBundle\Entity;
 
 use Doctrine\ORM\Mapping as ORM;
-use Symfony\Component\Serializer\Annotation as Serializer;
+use Symfony\Component\Serializer\Attribute as Serializer;
 
 /**
  * Class ActivityPresence.