Add chlily to //net/cookies/OWNERS

Bug: None
Change-Id: I62d87f2fcb30322e0f311de7dfdf1d0992d044e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1876793
Commit-Queue: Lily Chen <chlily@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708698}

net/cookies/OWNERS

+chlily@chromium.org
 estark@chromium.org
 mkwst@chromium.org
 mmenke@chromium.org