Update subresources.md

Unused post operation import

Author: orangevinz

core/subresources.md

@@ -303,7 +303,6 @@ namespace App\Entity;
 use ApiPlatform\Metadata\ApiResource;
 use ApiPlatform\Metadata\Get;
 use ApiPlatform\Metadata\Link;
-use ApiPlatform\Metadata\Post;
 use Doctrine\ORM\Mapping as ORM;
 
 #[ORM\Entity]