Upgrade to wallabag 2.6.4

Easy upgrade of Docker container to new micro version with version bumps of dependencies.

Database migration runs smoothly and exited successfully.

docker exec -t bierochs-wallabag /var/www/wallabag/bin/console doctrine:migrations:migrate --env=prod --no-interaction


 [OK] Already at the latest version ("Application\Migrations\Version20230613121354")