Update symfony/symfony to version v2.8.17 to remove deprecation warnings.
Update symfony/symfony to version v2.8.17 to remove deprecation warnings.

jonasdekeukelaere/Framework,jonasdekeukelaere/Framework,sumocoders/Framework,sumocoders/Framework,sumocoders/Framework,jonasdekeukelaere/Framework,sumocoders/Framework,jonasdekeukelaere/Framework