Update code to ArduinoJSON 6

src/main.cpp

@@ -264,28 +264,26 @@ void transmitStatus() {
     pres = bme280.readPressure();
   }
 
-  StaticJsonBuffer<200> jsonBuffer;
-  JsonObject& root = jsonBuffer.createObject();
+  StaticJsonDocument<200> jsonDocument;
   if (bme280.valid) {
-    root["temperature"] = temp;
-    root["humidity"] = humi;
-    root["pressure"] = pres;
+    jsonDocument["temperature"] = temp;
+    jsonDocument["humidity"] = humi;
+    jsonDocument["pressure"] = pres;
   } else {
-    //root["temperature"] = internal_temp;
+    //jsonDocument["temperature"] = internal_temp;
   }
 
-  char weatherBuf[root.measureLength()+1];
-  root.printTo(weatherBuf, sizeof(weatherBuf));
+  char weatherBuf[measureJson(jsonDocument)+1];
+  serialize(jsonDocument, weatherBuf, sizeof(weatherBuf));
   uint16_t statusPacketIdSub;
   statusPacketIdSub = iot.mqtt.publish(weatherTopic.c_str(), 0, false, weatherBuf);
 
-  StaticJsonBuffer<200> jsonBuffer2;
-  JsonObject& root2 = jsonBuffer2.createObject();
-  root2["voltage"] = rom_phy_get_vdd33();
-  root2["rssi"] = WiFi.RSSI();
-  root2["heap"] = ESP.getFreeHeap();
-  char statusBuf[root2.measureLength()+1];
-  root2.printTo(statusBuf, sizeof(statusBuf));
+  StaticJsonDocument<200> jsonDocument2;
+  jsonDocument2["voltage"] = rom_phy_get_vdd33();
+  jsonDocument2["rssi"] = WiFi.RSSI();
+  jsonDocument2["heap"] = ESP.getFreeHeap();
+  char statusBuf[measureJson(jsonDocument2)+1];
+  serialize(jsonDocument2, statusBuf, sizeof(statusBuf));
   statusPacketIdSub = iot.mqtt.publish(statusTopic.c_str(), 0, false, statusBuf);
 }