feat(web): 🎸 Add getLayerBoundingBox method usage example

.changeset/nervous-trains-dream.md

@@ -7,11 +7,19 @@ feat(web): 🎸 added `getLayerBoundingBox` method
 Basic usage:
 
 ```typescript
-// Draw a rectangle around the layer 'Layer 1'
+const canvas = document.getElementById('dotLottie-canvas');
+
+const dotLottie = new DotLottie({
+  canvas,
+  ...
+});
+
+// Draw a rectangle around the layer 'Layer 1' after a frame is renderered
 dotLottie.addEventListener('render', () => {
   const boundingBox = dotLottie.getLayerBoundingBox('Layer 1');
+  const context = canvas.getContext('2d');
 
-  if (boundingBox) {
+  if (boundingBox && context) {
     const { x, y, width, height } = boundingBox;
     context.strokeRect(x, y, width, height);
   }