[RN8209] Fix in use switch value (#1572)

main/ZmqttDiscovery.ino

@@ -897,7 +897,7 @@ void pubMqttDiscovery() {
       {"sensor", "volt", "RN8209", "voltage", jsonVolt, "", "", "V"},
       {"sensor", "current", "RN8209", "current", jsonCurrent, "", "", "A"},
       {"sensor", "power", "RN8209", "power", jsonPower, "", "", "W"},
-      {"binary_sensor", "inUse", "RN8209", "power", jsonInuseRN8209, "", "", ""}
+      {"binary_sensor", "inUse", "RN8209", "power", jsonInuseRN8209, "on", "off", ""}
       //component type,name,availability topic,device class,value template,payload on, payload off, unit of measurement
   };