revproxy: update

examples/reverse_proxy/Caddyfile

@@ -1,6 +1,7 @@
 hydro.ac {
   reverse_proxy http://localhost:8888 {
     header_up x-real-ip {remote_host}
-    header_up x-real-host {hostport}
+    # caddy now add x-forwarded-host automatically.
+    # header_up x-forwarded-host {hostport}
   }
 }