Enable PHPStan

- Fix error for level 0 & 1 (level 7 has 699 errors...)
- Add `updated_at` to site_credential (so the `timestamps()` method applies correctly)

src/Wallabag/CoreBundle/Helper/RuleBasedTagger.php

@@ -6,6 +6,7 @@ use Psr\Log\LoggerInterface;
 use RulerZ\RulerZ;
 use Wallabag\CoreBundle\Entity\Entry;
 use Wallabag\CoreBundle\Entity\Tag;
+use Wallabag\CoreBundle\Entity\TaggingRule;
 use Wallabag\CoreBundle\Repository\EntryRepository;
 use Wallabag\CoreBundle\Repository\TagRepository;
 use Wallabag\UserBundle\Entity\User;