feat: defined health variable for player

src/car_player.hpp

@@ -21,6 +21,8 @@ public:
     void on_brake(Ref<InputEvent> event, float value);
     void on_accelerate(Ref<InputEvent> event, float value);
 private:
+    int health{0};
+
     const float max_speed{40.f};
     const float max_speed_reverse{10.f};
     const float steering_factor{2.f};