Update example to use HSTS

Author: doublez13

stack-examples/wordpress/docker-compose.yml

@@ -24,6 +24,7 @@ services:
         - "traefik.http.routers.wordpress-secured.tls=true"
         - "traefik.http.routers.wordpress-secured.tls.certresolver=myresolver"
         - "traefik.http.services.wordpress.loadbalancer.server.port=80"
+        - "traefik.http.routers.wordpress-secured.middlewares=hsts@file"
 
   db:
     image: mysql:5.7