Add cwallez@, enga@, kainino@ as gpu/command_buffer OWNERS for WebGPU

Corentin, Austin, and Kai are responsible for WebGPU in Chromium and
the integration between Dawn's remoting protocol and Chromium's IPC.

Bug: none
Change-Id: I2b3b5d9cd6fea6c1d235d52cca144c35479f1522
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2067220Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743281}

gpu/command_buffer/OWNERS

@@ -7,4 +7,9 @@ zmo@chromium.org
 per-file *gpu_memory_buffer*=reveman@chromium.org
 per-file *gpu_memory_buffer*=dcastagna@chromium.org
 
+# For Dawn / WebGPU changes
+cwallez@chromium.org
+enga@chromium.org
+kainino@chromium.org
+
 # COMPONENT: Internals>GPU>Internals