sysutils/graylog: update to 4.0.2

ChangeLog: https://www.graylog.org/post/announcing-graylog-v4-02

Submitted by: Charles Gonçalves <charles@freebsdbrasil.com.br>
Reviewed by: dch (maintainer)
Sponsored by: SkunkWerks, GmbH
Sponsored by: FreeBSD Brasil
Differential Revision: https://reviews.freebsd.org/D28380