Deprecate renderpass color/depth .attachment

As of https://github.com/gpuweb/gpuweb/pull/1352 the spec indicates that
GPURenderPassColorAttachmentDescriptor and
GPURenderPassDepthStencilAttachmentDescriptor should use .view rather
than .attachment to indicate the TextureView associated with the
render pass attachment.

Bug: dawn:762
Change-Id: I70d615e19d8e7aae5b26aa5965c7109289ab868b
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/47902
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Brandon Jones <bajones@chromium.org>

src/utils/WGPUHelpers.cpp

@@ -104,14 +104,14 @@ namespace utils {
         uint32_t colorAttachmentIndex = 0;
         for (const wgpu::TextureView& colorAttachment : colorAttachmentInfo) {
             if (colorAttachment.Get() != nullptr) {
-                cColorAttachments[colorAttachmentIndex].attachment = colorAttachment;
+                cColorAttachments[colorAttachmentIndex].view = colorAttachment;
             }
             ++colorAttachmentIndex;
         }
         colorAttachments = cColorAttachments.data();
 
         if (depthStencil.Get() != nullptr) {
-            cDepthStencilAttachmentInfo.attachment = depthStencil;
+            cDepthStencilAttachmentInfo.view = depthStencil;
             depthStencilAttachment = &cDepthStencilAttachmentInfo;
         } else {
             depthStencilAttachment = nullptr;