Adding build of multi-value-sketch example to CI build

Author: aentinger

.travis.yml

@@ -65,6 +65,7 @@ install:
 script:
   - buildExampleSketch ArduinoIoTCloud_LED_switch
   - buildExampleSketch ArduinoIoTCloud_Travis_CI
+  - buildExampleSketch MultiValue_example
   - |
     if [ "$BOARD" == "arduino:samd:mkr1000" ] || [ "$BOARD" == "arduino:samd:mkrwifi1010" ];
     then buildExampleSketch WiFi_Cloud_Blink;