fix(hydra): owl:maxCardinality should be an int

Author: soyuka

src/Hydra/Serializer/DocumentationNormalizer.php

@@ -527,7 +527,7 @@ private function getProperty(ApiProperty $propertyMetadata, string $propertyName
         }
 
         if ($this->isSingleRelation($propertyMetadata)) {
-            $property['owl:maxCardinality'] = true;
+            $property['owl:maxCardinality'] = 1;
         }
 
         return $property;