Add mqtt folder in iotd

guowenxue

2021-04-20 b5bf869dfb976503ec146d79b588eeff61f13e50

 modules/c/ds18b20.c

@@ -32,7 +32,7 @@
                return 1;
        }

        printf("DS19B20 get temperature: %f ℃\n", temp);
        printf("DS18B20 get temperature: %f ℃\n", temp);
        return 0;
}