Update register initializer/terminator in README

Referencing https://github.com/godotengine/godot-cpp/pull/750

README.md

@@ -79,19 +79,23 @@ extern "C" {
 GDNativeBool GDN_EXPORT example_library_init(const GDNativeInterface *p_interface, const GDNativeExtensionClassLibraryPtr p_library, GDNativeInitialization *r_initialization) {
 	godot::GDExtensionBinding::InitObject init_obj(p_interface, p_library, r_initialization);
 
-	init_obj.register_scene_initializer(register_example_types);
-	init_obj.register_scene_terminator(unregister_example_types);
+	init_obj.register_initializer(initialize_example_module);
+	init_obj.register_terminator(uninitialize_example_module);
+	init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_SCENE);
 
 	return init_obj.init();
 }
 }
 ```
 
-The `register_example_types()` should register the classes in ClassDB, very like a Godot module would do.
+The `initialize_example_module()` should register the classes in ClassDB, very like a Godot module would do.
 
 ```cpp
 using namespace godot;
-void register_example_types() {
+void initialize_example_module(ModuleInitializationLevel p_level) {
+	if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
+		return;
+	}
 	ClassDB::register_class<Example>();
 }
 ```