PfSense acme certificates timeout fix

By default we might have following error with Acme plugin of pfSense.

xxxx/xx/xx xx:xx:xx [error] xxxxx#xxxxxx: *xxxx upstream timed out (60: Operation timed out) while reading response header from upstream, client: xxx.xxx.xxx.xxx, server: , request: "POST /acme/acme_certificates.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php-fpm.socket", 

How to fix:

In pfsense, the nginx conf file is at /etc/inc/system.inc

 keepalive_timeout  300;
 proxy_read_timeout 3600;