www/mybb: Update to 1.8.13

Set ignore with PHP 70, 71 and 72

Changelog:
https://blog.mybb.com/2017/11/07/mybb-1-8-13-released-security-maintenance-release/

MFH: 2017Q4
Approved by: xxx (mentor)
#Differential Revision: https://reviews.freebsd.org/Dxxxxx

vuxml:
security/vuxml: make validate [18:44:16]
/bin/sh /usr/home/joneum/dev/ports/security/vuxml/files/tidy.sh "/usr/home/joneum/dev/ports/security/vuxml/files/tidy.xsl" "/usr/home/joneum/dev/ports/security/vuxml/vuln.xml" > "/usr/home/joneum/dev/ports/security/vuxml/vuln.xml.tidy"

Validating...

/usr/local/bin/xmllint --valid --noout /usr/home/joneum/dev/ports/security/vuxml/vuln.xml

Successful.

Checking if tidy differs...
... seems okay
Checking for space/tab...
... seems okay
/usr/local/bin/python2.7 /usr/home/joneum/dev/ports/security/vuxml/files/extra-validation.py /usr/home/joneum/dev/ports/security/vuxml/vuln.xml

www/mybb: portlint -AC [18:52:08]
WARN: Makefile: for new port, make $FreeBSD$ tag in comment section empty, to make SVN happy.
0 fatal errors and 1 warning found.

I set PHP ignore for 70, 71 and 72, example: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=222173

I did not find anything to build this port with PHP 70,71 and 72. Do my mentors have an idea here?

#PHP56
11.1-amd64
11.1-i386

#PHP7.0
11.1-amd64-PHP70
11.1-i386-PHP70

#PHP7.1
11.1-amd64-PHP71
11.1-i386-PHP71

#PHP7.2
11.1-amd64-PHP72
11.1-i386-PHP72