change: remove docker from unattended upgrade origines

templates/apt-unattended-upgrades.j2

@@ -2,7 +2,6 @@ Unattended-Upgrade::Allowed-Origins {
     "${distro_id}:${distro_codename}";
     "${distro_id}:${distro_codename}-security";
     "${distro_id}:${distro_codename}-updates";
-    "Docker:${distro_codename}";
     "elastic:stable";
 {% if inventory_hostname in groups.gitlab %}
     "packages.gitlab.com/gitlab/gitlab-ce:${distro_codename}";