Update README.md

Author: SimonDanisch

README.md

@@ -58,6 +58,6 @@ vf_matrix = view_factors(bvh; rays_per_triangle=1000)
 ## Documentation
 
 - [Full API Documentation](https://juliageometry.github.io/Raycore.jl/)
-- [Ray Tracing Tutorial](https://juliageometry.github.io/Raycore.jl/raytracing_tutorial.html) - Build a complete ray tracer from scratch
+- [Ray Tracing Tutorial](https://juliageometry.github.io/Raycore.jl/dev/raytracing_tutorial.html) - Build a complete ray tracer from scratch
 
 ![Ray tracing example](./docs/src/raytracing.png)