add uk.planet.wikimedia.org (Ukrainian language)

Ukrainian planet, requested by User:Dolyn in 2012,
now has working feeds

https://meta.wikimedia.org/w/index.php?title=Planet_Wikimedia%2FNew_language&diff=6014128&oldid=6013755

Change-Id: I3152983bf019ea65ab847999fcd96217bbeda912