add X-Forwarded-Port in nginx reverse proxy for jetpack

jetpack require X-Forward for the port, or "requested method jetpack.jsonAPI does not exist"
ref: https://github.com/ViBiOh/docker-wordpress/issues/1

setup/start/nginx/appconfig.ejs

@@ -56,6 +56,7 @@ server {
     proxy_set_header   Host               $host;
     proxy_set_header   X-Forwarded-For    $remote_addr;
     proxy_set_header   X-Forwarded-Host   $host;
+    proxy_set_header   X-Forwarded-Port   $server_port;
     proxy_set_header   X-Forwarded-Proto  https;
     proxy_set_header   X-Forwarded-Ssl    on;