configuration.md - types for Tasksettings

Hello,

just wanna report a minor issue.

In **docs/sections/configuration.md** under Task configuration there is no type for public $timeout and public $retries.

If you try to use it that way you get a Fatal error:
Fatal error: Type of App\Queue\ExampleTask::$retries must be ?int (as in class Queue\Queue\Task) in ...