Fix namespace in StatisticsUpdated.php

[Namoshek]

The spelling mistake will cause the following error when the queue worker tries to unserialize the event class:

method_exists(): The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition "BeyondCode\LaravelWebsockets\Statistics\Events\StatisticsUpdated" of the object you are trying to operate on was loaded before unserialize() gets called or provide an autoloader to load the class definition

This may be a Windows specific bug, otherwise there would have been more reports I guess.

Btw. I also searched the other files for spelling mistakes in the namespaces, but everything looks fine.

[mpociot]

Thank you for finding this! I merged #33 instead, as it fixed all namespace issues.

[Namoshek]

Now I'm wondering why I didn't find the other occurences with global search + match case. 😕