bump lesson-builder

I'm worried this will break something but YOLO!

Author: greggman

package.json

@@ -4,7 +4,7 @@
   "description": "Some WebGL2 Tutorials designed for real WebGL and not 20yr old OpenGL",
   "main": "index.js",
   "devDependencies": {
-    "@gfxfundamentals/lesson-builder": "git+https://github.com/gfxfundamentals/lesson-builder.git#v1.17.5",
+    "@gfxfundamentals/lesson-builder": "github:gfxfundamentals/lesson-builder#v2.4.1",
     "@gfxfundamentals/live-editor": "github:gfxfundamentals/live-editor#v1.3.1",
     "eslint-plugin-google-camelcase": "0.0.2",
     "eslint-plugin-html": "6.1.1",