message: Update Arduino CLI tool installatation script to use permanent URL
  See for the context of this change.
diff: @@ -21,8 +21,8 @@ set -e
  cd /tmp
  rm -rf arduino-cli*
  -curl -L -O "https://downloads.arduino.cc/arduino-cli/arduino-cli-latest-linux64.tar.bz2"
  -tar xjf arduino-cli-latest-linux64.tar.bz2
  +curl -L -O "https://github.com/arduino/arduino-cli/releases/download/0.4.0/arduino-cli_0.4.0_Linux_64bit.tar.gz"
  +tar xzf arduino-cli_0.4.0_Linux_64bit.tar.gz
  /tmp/arduino-cli core update-index
  /tmp/arduino-cli core install arduino:mbed
  