net/kamailio: Update 6.1.1 => 6.1.3

Release Notes:
https://www.kamailio.org/w/2026/04/kamailio-v6-1-2-released/
https://www.kamailio.org/w/2026/05/kamailio-v6-1-3-released/

While here replace http with https in MASTER_SITES.

PR: 295692
Sponsored by: UNIS Labs