Update homepage 8-18-24 (#1690)

* Update featured challenges and showcases

* Update index.json

add dragon curve to featured challenges

Author: kfahn22

content/pages/homepage/index.json

@@ -32,11 +32,11 @@
     "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": [
       "185-dragon-curve",
-      "64-kinematics",
-      "125-fourier-series",
-      "28-metaballs",
-      "116-lissajous-curve-table",
-      "170-monty-hall-problem"
+      "175-3D-cube-applesoft-basic",
+      "160-spring-forces",
+      "113-4d-hypercube-aka-tesseract",
+      "99-neural-network-color-predictor",
+      "85-the-game-of-life"
     ],
     "challengesCta": {
       "text": "ready to explore? try a challenge!",
@@ -46,16 +46,7 @@
   },
   "passengerShowcase": {
     "title": "Passenger showcase highlights",
-    "featured": [
-      "challenges/160-spring-forces/showcase/contribution-1717812105.json",
-      "noc/4-particles/1-particle-system/showcase/contribution-1716063723.json",
-      "challenges/183-mathematical-marbling/showcase/contribution-5.json",
-      "challenges/183-mathematical-marbling/showcase/contribution-1719747682.json",
-      "challenges/93-double-pendulum/showcase/contribution-1717095241.json",
-      "code/2-variables/5-map/showcase/contribution-1719881442.json",
-      "noc/3-angles/7-additive-waves/showcase/contribution-1719068587.json",
-      "challenges/10-dfs-maze-generator/showcase/contribution-1719932734.json"
-    ],
+     "featured": ["challenges/184-elastic-collisions/showcase/contribution-1720963615.json", "challenges/184-elastic-collisions/showcase/contribution-1720958474.json", "noc/4-particles/4-particle-textures/showcase/contribution-1721161051.json", "physics-libraries/box2d/12-collision-events/showcase/contribution-1722000424.json", "challenges/14-fractal-trees-recursive/showcase/contribution-1723666252.json", "challenges/10-dfs-maze-generator/showcase/contribution-1720952091.json", "challenges/184-elastic-collisions/showcase/contribution-1721016798.json", "challenges/100-neuroevolution-flappy-bird/showcase/contribution-1720945862.json"],
     "showcaseCta": {
       "text": "Want to see more?",
       "buttonText": "Browse the full showcase",