Updated README.md with example working under openhab 3.0.
The receivedEvent does no longer have a method getEvent().
```
The optional `<EVENT>` represents one of the button events that are generated by the Hue Dimmer Switch.
-If ommited the rule gets triggered by any key action and you can determine the event that triggered it with the `receivedEvent.getEvent()` method.
+If ommited the rule gets triggered by any key action and you can determine the event that triggered it with the `receivedEvent` method.
Be aware that the events have a '.0' attached to them, like `2001.0` or `34.0`.
So, testing for specific events looks like this:
```php
-if (receivedEvent.getEvent() == "1000.0")) {
+if (receivedEvent == "1000.0")) {
//do stuff
}
```