tipp10: add sigmanificient in maintainers

pkgs/applications/misc/tipp10/default.nix

···
     mainProgram = "tipp10";
     homepage = "https://gitlab.com/tipp10/tipp10";
     license = licenses.gpl2Only;
-    maintainers = with maintainers; [ ];
+    maintainers = with maintainers; [ sigmanificient ];
     platforms = platforms.all;
   };
 }