devel/phpunit6: update from 6.1.4 to 6.2.2

[joneum]

Summary

• Update from 6.1.4 to 6.2.2
• 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 -p8 and PHP 7.0

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