Add alph@ as co-owner of Browser DevTools protocol.

Two of the current owners have left the Chrome Devtools team, and a
backup for caseq@ is needed.

Bug: none
Change-Id: I978a716681513b4f6ec9ae498cdbdf2da021f809
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1618458
Auto-Submit: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664552}

third_party/blink/renderer/core/inspector/OWNERS

@@ -6,6 +6,7 @@ pfeldman@chromium.org
 # Changes to remote debugging protocol require devtools review to
 # ensure backwards compatibility and committment to maintain.
 per-file browser_protocol.pdl=set noparent
+per-file browser_protocol.pdl=alph@chromium.org
 per-file browser_protocol.pdl=dgozman@chromium.org
 per-file browser_protocol.pdl=caseq@chromium.org
 per-file browser_protocol.pdl=pfeldman@chromium.org