Update ReadField.ino

Fixed missing semicolon

Author: jasontwinters

examples/ArduinoYun/ReadField/ReadField.ino

@@ -28,7 +28,7 @@
 #include "ThingSpeak.h"
 #include "YunClient.h"
 #include "secrets.h"
-YunClient client
+YunClient client;
 
 // Weather station channel details
 unsigned long weatherStationChannelNumber = SECRET_CH_ID_WEATHER_STATION;