Change module apt with multiple packages to remove deprecated syntax

tasks/vpn.yml

@@ -3,10 +3,11 @@
 
 - name: "Install extra packages"
   apt:
-    name: '{{ item }}'
+    name: '{{ packages }}'
     state: 'present'
-  with_items:
-    - 'strongswan'
+  vars:
+    packages:
+      - 'strongswan'
 
 - name: "Configure IPSec"
   template: