Updated mediawiki/skins
Project: mediawiki/skins/BlueSky  2635a9b0ad3821dbb0e86a3b8cd83cfa76c5adef

External link icons support.

* 1.23 and older
* 1.24
** with https://gerrit.wikimedia.org/r/#/c/143173/ merged
** without the above patchset merged

Change-Id: Ic2031dc3f2be6fa1e77a9cd234ee4af89308de7c