net-mgmt/zabbix5: Update to 5.0.13

Changelog: https://www.zabbix.com/rn/rn5.0.13
Differential Revision: https://reviews.freebsd.org/D30964

Approved by: pg@pakhom.spb.ru (maintainer)

(cherry picked from commit 443da42db1f36fdae98a951a4e771a78a8bdd0de)