Make huangs OWNER of tools/gritsettings

Change-Id: Icb892aa6fec0fd5f38582f604bbe8e81bcfccdaa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1849097
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Peter Wen <wnwen@chromium.org>
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704252}

tools/gritsettings/OWNERS

 file://tools/grit/OWNERS
+
+huangs@chromium.org