Add szuend to OWNERS files for src/{debug,inspector}

R=yangguo@chromium.org

Change-Id: Ia58394ec14b34dcd9641d6cf3a810ac272431801
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1958006
Commit-Queue: Simon Zünd <szuend@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Auto-Submit: Simon Zünd <szuend@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65379}

src/debug/OWNERS

 bmeurer@chromium.org
 jgruber@chromium.org
 mvstanton@chromium.org
+szuend@chromium.org
 verwaest@chromium.org
 yangguo@chromium.org
 

src/inspector/OWNERS

@@ -3,6 +3,7 @@ caseq@chromium.org
 dgozman@chromium.org
 kozyatinskiy@chromium.org
 pfeldman@chromium.org
+szuend@chromium.org
 yangguo@chromium.org
 
 per-file PRESUBMIT.py=file:../../INFRA_OWNERS