Fix deprecations

Author: javer

src/DependencyInjection/Compiler/Endpoints/DefaultEndpointWiringPass.php

@@ -10,7 +10,7 @@
 final class DefaultEndpointWiringPass implements CompilerPassInterface
 {
     // @todo https://github.com/symfony/symfony/blob/master/src/Symfony/Component/DependencyInjection/Tests/Compiler/RemoveUnusedDefinitionsPassTest.php
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $endpointDefinition = $container->getDefinition('overblog_graphiql.controller.graphql.endpoint');
 

src/DependencyInjection/Compiler/Endpoints/OverblogGraphQLBundleEndpointWiringPass.php

@@ -9,7 +9,7 @@
 
 final class OverblogGraphQLBundleEndpointWiringPass implements CompilerPassInterface
 {
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $bundles = $container->getParameter('kernel.bundles_metadata');