Update .travis.yml

Author: fischermoseley

.travis.yml

@@ -8,7 +8,7 @@ before_install:
   - sudo mv arduino-1.8.9 /usr/local/share/arduino
   - sudo ln -s /usr/local/share/arduino/arduino /usr/local/bin/arduino
 install:
-  - arduino-cli core install arduino:samd
+  - arduino core install arduino:samd
   - ln -s $PWD /usr/local/share/arduino/libraries/SparkFun_MCP9600_Arduino_Library
   - pwd
   - ls -lai