Add sophiechang and falken to predictors OWNERS

Change-Id: I6cfecc37b262308f0ca557ec51dd876b53aa12cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2298162Reviewed-by: Sophie Chang <sophiechang@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#788477}

chrome/browser/predictors/OWNERS

 alexilin@chromium.org
+falken@chromium.org
 lizeb@chromium.org
 pasko@chromium.org
+sophiechang@chromium.org
 tbansal@chromium.org
 
 # COMPONENT: Internals>Preload