update code to work with Symfony 5

Author: MasaakiYoshida

src/DependencyInjection/Compiler/ReplaceFileLoadersPass.php

@@ -54,7 +54,7 @@ public function process(ContainerBuilder $container)
                 case 'addYamlMappings':
                     $metadataFactoryFactoryDefinition->addMethodCall($method, $arguments);
                     break;
-                case 'enableAnnotationMapping':
+                case 'setDoctrineAnnotationReader':
                     $metadataFactoryFactoryDefinition->addMethodCall('setAnnotationReader', array(clone $arguments[0]));
                     break;
                 case 'setMetadataCache':

src/DependencyInjection/Configuration.php

@@ -30,8 +30,8 @@ class Configuration implements ConfigurationInterface
     public function getConfigTreeBuilder()
     {
         $defaultConstraintNamespaces = self::$defaultConstraintNamespaces;
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('phpmentors_validator')
+        $treeBuilder = new TreeBuilder('phpmentors_validator');
+        $treeBuilder->getRootNode()
             ->children()
                 ->arrayNode('constraint')
                     ->addDefaultsIfNotSet()