Rename RenderPassDepthStencilAttachmentDescriptor

Rename RenderPassDepthStencilAttachmentDescriptor -> RenderPassDepthStencilAttachment

See: https://docs.rs/wgpu/0.8.1/wgpu/struct.RenderPassDepthStencilAttachment.html

docs/beginner/tutorial8-depth/README.md

@@ -142,7 +142,7 @@ The last change we need to make is in the `render()` function. We've created the
 ```rust
 let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
     // ...
-    depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachmentDescriptor {
+    depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
         view: &self.depth_texture.view,
         depth_ops: Some(wgpu::Operations {
             load: wgpu::LoadOp::Clear(1.0),