Freeze break request: update mediawiki

[Patrick マルタインアンドレアス Uiterwijk]

Hello,

So today a mediawiki security update was released (v1.19.5), with some fixes being for
remote script invocation.
I would like to request a freeze break to update this on the app servers in production.
In staging, the update has been succesful, and no database changes are needed.

Thanks in advance,
Patrick Uiterwijk