maintainers: create sage team

Maintaining all the packages whose updates might break some aspect of
sage.

For reference:
https://github.com/NixOS/nixpkgs/pull/103810#issuecomment-727536510

pkgs/development/libraries/cddlib/default.nix

@@ -26,7 +26,7 @@ stdenv.mkDerivation rec {
     inherit version;
     description = ''An implementation of the Double Description Method for generating all vertices of a convex polyhedron'';
     license = licenses.gpl2Plus;
-    maintainers = with maintainers; [raskin timokau];
+    maintainers = with maintainers; [raskin] ++ teams.sage.members;
     platforms = platforms.unix;
     homepage = "https://www.inf.ethz.ch/personal/fukudak/cdd_home/index.html";
   };