zotero: remove ttuegel from maintainers

I don't use Zotero at all anymore, and the Firefox plugin was much more
reliable than the standalone version in my experience.

pkgs/applications/office/zotero/default.nix

···
     description = "Collect, organize, cite, and share your research sources";
     license = licenses.agpl3;
     platforms = platforms.linux;
-    maintainers = with maintainers; [ ttuegel ];
   };
 }