WebGPU code refresh needed: layout parameter now required in createRenderPipeline calls

The WebGPU specification (and implementation in Chrome) has evolved slightly since the samples were written. The layout parameter is now required when calling createRenderPipeline or createComputePipeline. Adding layout: 'auto' in calls to createRenderPipeline could be enough to fix that part (unless the code uses a more specific pipeline).

(That said, I think that some of the constructs in WGSL need updating too. I haven't tried to dig into that.)