attempt to fix syntax error on python3.5

```
E     File "/home/runner/work/systemctl-mqtt/systemctl-mqtt/systemctl_mqtt/__init__.py", line 56
E       ) -> None:
E       ^
E   SyntaxError: invalid syntax
```

https://github.com/fphammerle/systemctl-mqtt/runs/1355338403

systemctl_mqtt/__init__.py

@@ -48,7 +48,6 @@ _LOGGER = logging.getLogger(__name__)
 class _State:
     def __init__(
         self,
-        *,
         mqtt_topic_prefix: str,
         homeassistant_discovery_prefix: str,
         homeassistant_node_id: str,