devel/phpunit6: Update from 6.2.2 to 6.2.3

[joneum]

Summary

• devel/phpunit6: version 6.2.2 to 6.2.3
• Changelog: https://github.com/sebastianbergmann/phpunit/blob/master/ChangeLog-6.2.md

Approved by: xxx (mentor)
#Differential Revision: https://reviews.freebsd.org/Dxxxxx

Test Plan

:~/dev/ports/devel/phpunit6 % portlint -AC
WARN: Makefile: for new port, make $FreeBSD$ tag in comment section empty, to make SVN happy.
0 fatal errors and 1 warning found.

Update tested in VirtualBox with FreeBSD 11.0 -p10 and PHP 7.1

Poudriere works with PHP 56 and cannot installed this Port (doesn't support PHP 5.6)