Enable the pkgfile-update timer instead of the service

We want to periodically update it, not when we deploy the role :)

roles/phrik/tasks/main.yml

@@ -37,5 +37,5 @@
     state: started
     daemon_reload: yes
   with_items:
-    - pkgfile-update.service
+    - pkgfile-update.timer
     - phrik.service