Remove yutak@chromium.org from Source/modules/websockets/OWNERS

He's no longer actively working on this component. Remove him from
OWNERS for now.

BUG=none

Review URL: https://codereview.chromium.org/238483004

git-svn-id: svn://svn.chromium.org/blink/trunk@171748 bbb929c8-8fbe-4397-9dbb-9b2b20218538