Remove petermarshall from OWNERS

Bug: none
Change-Id: Ifd381c70bc50ad85c7f2367c821be876b325d0fc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2793967
Auto-Submit: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73735}

COMMON_OWNERS

@@ -28,7 +28,6 @@ mythria@chromium.org
 neis@chromium.org
 nicohartmann@chromium.org
 omerkatz@chromium.org
-petermarshall@chromium.org
 pthier@chromium.org
 rmcilroy@chromium.org
 sigurds@chromium.org

src/profiler/OWNERS

 bmeurer@chromium.org
 cbruni@chromium.org
-petermarshall@chromium.org
 yangguo@chromium.org
 
 per-file *heap*=ulan@chromium.org

src/protobuf/OWNERS

-petermarshall@chromium.org
 cbruni@chromium.org