add a changelog

changelog/unreleased/move-indexer-to-ocis-pkg.md

@@ -0,0 +1,5 @@
+Change: Move the indexer package from ocis/accounts to ocis/ocis-pkg
+
+We are making that change for semantic reasons. So consumers of any index don't necessarily need to know of the accounts service.
+
+https://github.com/owncloud/ocis/pull/794