Add proberge@ as OWNER of chrome_cleaner

Bug: 
Change-Id: I51c7f5c4b508b2846ba7af0feeee8085ca5e362c
Reviewed-on: https://chromium-review.googlesource.com/810054Reviewed-by: Chris Sharp <csharp@chromium.org>
Commit-Queue: Fabio Tirelo <ftirelo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522099}

chrome/browser/safe_browsing/chrome_cleaner/OWNERS

 csharp@chromium.org
 joenotcharles@chromium.org
+proberge@chromium.org
 robertshield@chromium.org
 
 # COMPONENT: UI>Browser>Preferences>Protector

components/chrome_cleaner/OWNERS

 csharp@chromium.org
 joenotcharles@chromium.org
+proberge@chromium.org
 robertshield@chromium.org
 
 # TEAM: security-dev@chromium.org