update command name to match class name

It will fix a problem in the EventSourcingServiceProvider:54, where the clear command is typed differently from the command signature.

src/Console/ClearCachedEventHandlersCommand.php

@@ -7,7 +7,7 @@
 
 class ClearCachedEventHandlersCommand extends Command
 {
-    protected $signature = 'event-sourcing:clear-event-handlers';
+    protected $signature = 'event-sourcing:clear-cached-event-handlers';
 
     protected $description = 'Clear cached event handlers';