{% set def_rel = 'bullseye' %}
{% if salt['pillar.get']('os:release', default = False) %}
{%   set def_rel = salt['pillar.get']('os:release', default = False) %}
{% endif %}

etc_apt_release:
  file.managed:
    - name: /etc/apt/apt.conf.d/01release
    - user: root
    - mode: 644
    - contents: 'APT::Default-Release "{{ def_rel }}";'