Log Message:
www/SOGo: update to 2.3.23

2.3.23 (2017-10-18)
-------------------

Enhancements
 - [web] added Simplified Chinese (zh_CN) translation - thanks to Thomas Kuiper
 - [web] updated CKEditor to version 4.7.3

Bug fixes
 - [core] yearly repeating events are not shown in web calendar (#4237)
 - [core] correctly handle "Last day of the month" recurrence rule
 - [core] fixed yearly recurrence calculator with until date
 - [core] generalized HTML sanitization to avoid encoding issues when \ 
replying/forwarding mails
 - [eas] avoid sync requests for shared folders every second (#4275)