Some pending deprectaion messages in SF 6.4

[davidromani]

PHP Deprecated:  SM\Callback\CascadeTransitionCallback::apply(): Implicitly marking parameter $graph as nullable is deprecated, the explicit nullable type must be used instead in vendor/winzou/state-machine/src/SM/Callback/CascadeTransitionCallback.php on line 43
SM\Factory\Factory::__construct(): Implicitly marking parameter $dispatcher as nullable is deprecated, the explicit nullable type must be used instead in vendor/winzou/state-machine/src/SM/Factory/Factory.php on line 32
SM\Factory\Factory::__construct(): Implicitly marking parameter $callbackFactory as nullable is deprecated, the explicit nullable type must be used instead in vendor/winzou/state-machine/src/SM/Factory/Factory.php on line 32

[davidromani]

PR to solve it provided here https://github.com/winzou/StateMachineBundle/pull/71