roles/common: remove cron-apt

Use unattended-upgrades instead. It has sane defaults on Debian at
least (I haven't checked Ubuntu).

roles/common/tasks/packages_Debian.yml

@@ -22,7 +22,6 @@
           - iotop
           - htop
           - strace
-          - cron-apt
           - safe-rm
           - debian-goodies
           - mosh
@@ -34,11 +33,12 @@
           - zstd
           - rsync
           - lsof
+          - unattended-upgrades
 
     - name: Install base packages
       ansible.builtin.apt: name={{ base_packages }} state=present cache_valid_time=3600
 
-    - name: Configure cron-apt
+    - name: Remove cron-apt
       ansible.builtin.import_tasks: cron-apt.yml
       tags: cron-apt