[Unbound] Define mailcow ip6 as private

data/conf/unbound/unbound.conf

@@ -19,6 +19,7 @@ server:
   private-address: 169.254.0.0/16
   private-address: fd00::/8
   private-address: fe80::/10
+  private-address: fd4d:6169:6c63:6f77::/64
   root-hints: "/etc/unbound/root.hints"
   hide-identity: yes
   hide-version: yes