GitLab

Rename public/README to README.md so that it can be rendered by Gitiles

Bug: 
Change-Id: Iff8f32b46b01b095ae50592fb2308bce4058e572
Reviewed-on: https://chromium-review.googlesource.com/597385Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Takeshi Yoshino <tyoshino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491291}