E: Unable to correct problems, you have held broken packages.
ERROR: Service 'php71' failed to build: The command '/bin/sh -c apt-get install -y --no-install-recommends libpng-dev libjpeg-dev libfreetype6-dev ntpdate cron vim unzip git' returned a non-zero code: 100
E: Unable to correct problems, you have held broken packages. ERROR: Service 'php71' failed to build: The command '/bin/sh -c apt-get install -y --no-install-recommends libpng-dev libjpeg-dev libfreetype6-dev ntpdate cron vim unzip git' returned a non-zero code: 100