Entry: add archived_at property and updateArchived method

src/Wallabag/ImportBundle/Import/PinboardImport.php

@@ -119,7 +119,7 @@ class PinboardImport extends AbstractImport
             );
         }
 
-        $entry->setArchived($data['is_archived']);
+        $entry->updateArchived($data['is_archived']);
         $entry->setStarred($data['is_starred']);
         $entry->setCreatedAt(new \DateTime($data['created_at']));