implementing Twig_Extension_InitRuntimeInterface in SonataAdminExtension to suppress twig deprecation message

Twig/Extension/SonataAdminExtension.php

@@ -24,7 +24,7 @@ use Symfony\Component\PropertyAccess\PropertyAccess;
  *
  * @author  Thomas Rabaix <thomas.rabaix@sonata-project.org>
  */
-class SonataAdminExtension extends \Twig_Extension
+class SonataAdminExtension extends \Twig_Extension implements \Twig_Extension_InitRuntimeInterface
 {
     /**
      * @var \Twig_Environment

composer.json

@@ -30,7 +30,7 @@
         "symfony/translation":"~2.3",
         "symfony/dependency-injection": "~2.3,>=2.3.3",
         "symfony/property-access": "~2.3",
-        "twig/twig": "~1.15",
+        "twig/twig": "~1.23",
         "twig/extensions": "~1.0",
         "sonata-project/exporter": "~1.0",
         "sonata-project/block-bundle": "^2.3.8",