Update index.json

add new video to homepage

Author: kfahn22

content/pages/homepage/index.json

@@ -31,7 +31,7 @@
     "title": "Challenges",
     "description": "Watch Dan take on Coding Challenges in p5.js and Processing. The challenge topics include algorithmic art, machine learning, simulation, generative poetry, and more.",
     "featured": [
-      "4-purple-rain",
+      "186-wfc-overlapping-model",
       "152-rdp-algorithm",
       "171-wave-function-collapse",
       "178-climate-spiral",