www/typo3-7: Update from 7.6.20 to 7.6.21

[joneum]

Summary

• www/typo3-7: Update from 7.6.20 to 7.6.21
• Changelog: https://typo3.org/news/article/typo3-874-and-7621-released/

PR: 221388
Submitted by: Helmut Ritter <[e-mail]> (maintainer)
Approved by: xxx (mentor)
#Differential Revision: https://reviews.freebsd.org/Dxxxxx

Test Plan

:~/dev/ports/www/typo3-7 % 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.

poudriere testport:

10.3-amd64
10.3-i386
11.1-amd64
11.1-i386
12.0-CURRENT r321899 amd64
12.0-CURRENT r321913 i386

[tz]

Approved with following changes:

• Changelog URL should be: https://wiki.typo3.org/TYPO3_CMS_7.6.21
• Add MFH for 2017Q3