Add devtools owners for inspect/

Change-Id: I043320f32a61676ee5c61524cf4a23fc3c65321d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2324382Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797183}

chrome/browser/resources/inspect/OWNERS

 dgozman@chromium.org
 pfeldman@chromium.org
 yangguo@chromium.org
+petermarshall@chromium.org
+sigurds@chromium.org
 
 # COMPONENT: Platform>DevTools