Remove unused serializer annotation.

src/Search.php

@@ -26,7 +26,6 @@ use ONGR\ElasticsearchDSL\SearchEndpoint\SearchEndpointInterface;
 use ONGR\ElasticsearchDSL\SearchEndpoint\SortEndpoint;
 use ONGR\ElasticsearchDSL\Serializer\Normalizer\CustomReferencedNormalizer;
 use ONGR\ElasticsearchDSL\Serializer\OrderedSerializer;
-use Symfony\Component\Serializer\Annotation\Groups;
 use Symfony\Component\Serializer\Normalizer\CustomNormalizer;
 
 /**