Update create_game.md

doc/create_game.md

@@ -243,6 +243,10 @@ Hint "now use `rw [{h}]` to use your assumption {h}."
 ```
 That way, the game will replace it with the actual name the assumption has in the player's proof state.
 
+## 7. Update your game
+
+In principle, it is as simple as modifying `lean-toolchain` to update your game to a new Lean version. However, you should read about the details in [Update An Existing Game](https://github.com/leanprover-community/lean4game/edit/main/doc/update_game.md).
+
 ## Further Notes
 
 Here are some random further things you should consider designing a new game: