Add sfiera to components/search/OWNERS

Bug: none
Change-Id: Ibb7291bf3e17228d93f95a05b801289cba55a864
Reviewed-on: https://chromium-review.googlesource.com/814314Reviewed-by: Chris Pickel <sfiera@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522422}

components/search/OWNERS

 treib@chromium.org
+sfiera@chromium.org
 
 # Original implementors of most of the code, but not active in Chromium anymore:
 # - jered@chromium.org