debian-updates: only manage aliases on pre-bullseye hosts

Although not strictly related, I found this to be the simplest solution as I expect modern hosts (bullseye and up) to have a ansible-managed mail setup. However, if you prefer I can change this to a separate variable.

debian-updates/tasks/main.yml

@@ -90,6 +90,7 @@
     line: '{{ apticron_to|regex_replace("@.*$") }}:"|/opt/debian-updates/receive.py"'
     path: /etc/aliases
     state: present
+  when: ansible_distribution_major_version|int(default=99) < 11
   notify:
     - rebuild alias database
   tags: