Update README.md

Author: gkjohnson

README.md

@@ -33,6 +33,8 @@ _More features and capabilities in progress!_
 
 [Area Light Support](https://gkjohnson.github.io/three-gpu-pathtracer/example/bundle/areaLight.html)
 
+[Spot Lights Support](https://gkjohnson.github.io/three-gpu-pathtracer/example/bundle/spotLights.html)
+
 **Test Scenes**
 
 [Material Test Orb](https://gkjohnson.github.io/three-gpu-pathtracer/example/bundle/materialBall.html)