Update to make our code compatible with Symfony 3 & 4
Created by: seamuslee001
This is as per core changes such as https://github.com/civicrm/civicrm-core/blob/master/Civi/Core/Container.php#L179
Created by: seamuslee001
This is as per core changes such as https://github.com/civicrm/civicrm-core/blob/master/Civi/Core/Container.php#L179