feat(roles): Add auto updating to some roles

Miniflux, searx, shaarli and wallabag will be automatically updated by
shepherd.

roles/shaarli/templates/docker-stack.yml.j2

@@ -14,6 +14,11 @@ services:
     volumes:
     - data:/var/www/shaarli/data
     - cache:/var/www/shaarli/cache
+{% if shaarli_autoupdate is defined and shaarli_autoupdate %}
+    deploy:
+      labels:
+        - shepherd.autoupdate=true
+{% endif %}
 
 {% if backup_enable is not undefined and not false and shaarli_backup_enable is not undefined and not false %}
   backup: