chinese/wordpress-zh_CN: Update from 4.7.4 to 4.8

[joneum]

Summary

• chinese/wordpress-zh_CN: Update from 4.7.4 to 4.8
• Changelog: https://wordpress.org/news/2017/06/evans/

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

Test Plan

~ % cd dev/ports/chinese/wordpress-zh_CN/
joneum@phantomias:~/dev/ports/chinese/wordpress-zh_TW % 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 r320266 amd64
12.0-CURRENT r320266 i386