feat: Precision support and default set to 0.1 on hass discovery clim…

…ate devices (#326)

lib/Gateway.js

@@ -773,7 +773,12 @@ Gateway.prototype.discoverDevice = function (node, hassDevice) {
         }
 
         let currTemp = node.values[payload.current_temperature_topic]
-        if (currTemp !== undefined) payload.current_temperature_topic = this.mqtt.getTopic(this.valueTopic(node, currTemp))
+        if (currTemp !== undefined) {
+          payload.current_temperature_topic = this.mqtt.getTopic(this.valueTopic(node, currTemp))
+          // hass will default the precision to 0.1 for Celsius and 1.0 for Fahrenheit.
+          // 1.0 is not granular enough as a default and there seems to be no harm in making it more precise.
+          if (!payload.precision) payload.precision = 0.1
+        }
       } else {
         payload = hassDevice.discovery_payload