fixing homepage and nebula slug

Author: shiffman

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": [
-      "179-wolfram-alpha",
+      "179-wolfram-ca",
       "89-langtons-ant",
       "98-quadtree",
       "70-nearest-neighbors-recommendation-engine",

content/videos/challenges/179-wolfram-ca/index.json

@@ -3,7 +3,7 @@
   "videoNumber": "179",
   "description": "How is nature hidden in a pile of 0s and 1s? Let's find out by coding a p5.js visualization of the Wolfram Elementary Cellular Automaton!",
   "videoId": "Ggxt06qSAe4",
-  "nebulaSlug": "https://nebula.tv/videos/codingtrain-wolfram-elementary-ca",
+  "nebulaSlug": "git codingtrain-wolfram-elementary-ca",
   "date": "2023-01-09",
   "languages": ["p5.js", "JavaScript"],
   "topics": ["nature of code", "wolfram", "ca", "cellular automata", "binary to decimal conversion", "Sierpinski triangle"],