[Travis] Formatting change

.travis.yml

@@ -30,7 +30,12 @@ before_install:
   - sudo iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
 
   # install 3rd party boards
-  - arduino --pref "boardsmanager.additional.urls=http://arduino.esp8266.com/stable/package_esp8266com_index.json,https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json,https://github.com/stm32duino/BoardManagerFiles/raw/master/STM32/package_stm_index.json,https://raw.githubusercontent.com/sparkfun/Arduino_Boards/master/IDE_Board_Manager/package_sparkfun_index.json" --save-prefs 2>&1
+  - arduino --pref 'boardsmanager.additional.urls=' \
+                   'http://arduino.esp8266.com/stable/package_esp8266com_index.json,' \
+                   'https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json,' \
+                   'https://github.com/stm32duino/BoardManagerFiles/raw/master/STM32/package_stm_index.json,' \
+                   'https://raw.githubusercontent.com/sparkfun/Arduino_Boards/master/IDE_Board_Manager/package_sparkfun_index.json' \
+                   --save-prefs 2>&1
   - if [[ "$BOARD" =~ "esp8266:esp8266:" ]]; then
       arduino --install-boards esp8266:esp8266;
       export SKIP_PAT='(HTTP|MQTT).*ino';