[Travis] Added missing tool for nRF52 TRAVIS_FORCE_BUILD

.travis.yml

@@ -18,6 +18,13 @@ env:
     - BOARD="SparkFun:apollo3:amap3redboard"
     - BOARD="arduino:mbed:nano33ble"
 
+addons:
+  apt:
+    packages:
+      - python3
+      - python3-pip
+      - python3-setuptools
+
 before_install:
   # install Arduino IDE
   - wget https://downloads.arduino.cc/arduino-$ARDUINO_IDE_VERSION-linux64.tar.xz
@@ -68,6 +75,7 @@ before_install:
       arduino --install-boards arduino:sam;
 
     elif [[ "$BOARD" =~ "adafruit:nrf52:" ]]; then
+      pip3 install --user adafruit-nrfutil
       export BUILD_EXAMPLES=false;
       arduino --pref "boardsmanager.additional.urls=https://www.adafruit.com/package_adafruit_index.json" --save-prefs 2>&1;
       arduino --install-boards adafruit:nrf52;