Remove a deprecation

Author: dunglas

src/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtension.php

@@ -19,8 +19,8 @@
 use Symfony\Component\Cache\Adapter\ArrayAdapter;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\Config\Resource\DirectoryResource;
+use Symfony\Component\DependencyInjection\ChildDefinition;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
-use Symfony\Component\DependencyInjection\DefinitionDecorator;
 use Symfony\Component\DependencyInjection\Extension\PrependExtensionInterface;
 use Symfony\Component\DependencyInjection\Loader\XmlFileLoader;
 use Symfony\Component\DependencyInjection\Reference;
@@ -388,7 +388,7 @@ private function registerHttpCache(ContainerBuilder $container, array $config, X
             $id = sprintf('api_platform.http_cache.purger.varnish_client.%s', $url);
             $references[] = new Reference($id);
 
-            $definition = new DefinitionDecorator('api_platform.http_cache.purger.varnish_client');
+            $definition = new ChildDefinition('api_platform.http_cache.purger.varnish_client');
             $definition->addArgument(['base_uri' => $url]);
             $container->setDefinition($id, $definition);
         }