The Wikidata dumps description in RDF given by DCAT-AP. Only refers to Wikimedia Foundation by name. I created a patch do use an additional URI.
Moreover there should be a link from the described dataset and Wikidata as project (http://www.wikidata.org/entity/Q2013). The data model is as following:
dcat:Catalog (list of Wikidata dumps)
dcat:Dataset (Wikidata dump of a specific date)
dcat:Distribution (particular dump file)
A dcat:Dataset could be connected to Wikidata URI via http://www.wikidata.org/entity/P629 (edition or translation of) because each Wikidata dump is a published edition of Wikidata. Shall I create another pull request to implement this or is there a better way to model the connection?