Update public/index.html

public/index.html

@@ -214,7 +214,7 @@
       loader.load("https://immersive-web.github.io/webxr-samples/media/gltf/sunflower/sunflower.gltf", (gltf) => {
         models.sunflower = gltf.scene;
       });
-      loader.load("https://immersive-web.github.io/webxr-samples/media/gltf/tree/tree.gltf", (gltf) => {
+      loader.load("https://github.com/KhronosGroup/glTF-Sample-Models/blob/main/2.0/Duck/glTF/Duck.gltf", (gltf) => {
         models.tree = gltf.scene;
       });