Install steam via saltstack

steam.sls

dpkg_steam_license:
  cmd.run:
    - unless: which steam
    - name: '/bin/echo /usr/bin/debconf steam/license note | /usr/bin/debconf-set-selections'
    - require_in:
      - pkg: steam
      - cmd: dpkg_steam_question

dpkg_steam_question:
  cmd.run:
    - unless: which steam
    - name: '/bin/echo /usr/bin/debconf steam/question select "I AGREE" | /usr/bin/debconf-set-selections'
    - require_in:
      - pkg: steam

steam:
  pkg.installed

Nice one!

This didn't work for me anymore.

This works on Ubuntu 16.04:

debconf-utils:
    pkg.installed

steam:
  debconf.set:
    - data:
        steam/question: {'type': 'select', 'value': 'I AGREE'}
        steam/license: {'type': 'note', 'value': ''}
    - require:
      - pkg: debconf-utils
  pkg.installed:
    - sources:
      - steam-launcher: https://steamcdn-a.akamaihd.net/client/installer/steam.deb
    - require:
      - debconf: steam