Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  dd4d553c0fde3d905ed606b9eb2dd5139044ad79

(Bug 47288) Abstraction layer for usage tracking.

This introduces the EntityUsageIndex for tracking which client
 pages used which entity.

Change-Id: I50dbac5760ec5cb331d3372545f1eac4e53a19bd