Merge pull request #7 from OpenClassrooms/OC-26223_sf_deprecations_tree_builder

https://simple-it.atlassian.net/browse/OC-26223

Author: DotnDev

DependencyInjection/Configuration.php

@@ -17,8 +17,8 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('openclassrooms_cache');
+        $treeBuilder = new TreeBuilder('openclassrooms_cache');
+        $rootNode = $treeBuilder->getRootNode();
         $rootNode
             ->children()
                 ->arrayNode('provider')