Jump to Symfony 3.4

Thanks to the BC compatibility, almost nothing have to be changed.
All changes are related to new bundle version of:
- SensioFrameworkExtraBundle
- DoctrineFixturesBundle

src/Wallabag/ImportBundle/Controller/WallabagV2Controller.php

@@ -2,8 +2,8 @@
 
 namespace Wallabag\ImportBundle\Controller;
 
-use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\Annotation\Route;
 
 class WallabagV2Controller extends WallabagController
 {