Merge pull request 'Set docker apt repo matching the Debian release' (!51) from docker_setup-release into master

Reviewed-on: https://gitea.n39.eu/Netz39_Admin/netz39-infra-ansible/pulls/51
Reviewed-by: Alexander Dahl <alex@netz39.de>
Fixes: #721

roles/docker_setup/tasks/main.yml

@@ -29,11 +29,15 @@
     state: present
 
 - name: add Docker's APT repository
-  apt_repository:
+  ansible.builtin.template:
-    repo: deb https://download.docker.com/linux/debian buster stable
+    src: templates/docker.list.j2
-    state: present
+    dest: /etc/apt/sources.list.d/docker.list
+  register: apt_repo
+
+- name: Update package cache
+  ansible.builtin.apt:
     update_cache: true
-    filename: "docker"
+  when: apt_repo.changed
 
 - name: install Docker
   package:

roles/docker_setup/templates/docker.list.j2

@@ -0,0 +1,2 @@
+deb https://download.docker.com/linux/debian {{ ansible_distribution_release }} stable
+