Merge pull request #4137 from robberer/bump/keepnote

keepnote: add myself as a maintainer

pkgs/applications/office/keepnote/default.nix

···
     description = "Note taking application";
     homepage = http://rasm.ods.org/keepnote;
     license = stdenv.lib.licenses.gpl2Plus;
+    maintainers = [ maintainers.robberer ];
   };
 }