Recent Commits to styleguide:gh-pages

CODEOWNERS: drop ex-Googlers

GitHub: Refresh Code Owners for Current Go Admins (#890)

The current Go Readability Approvers administration group has grown
over the last few years, so we should refresh the code owners to
make maintenance of the external style guide easier.  This also
lightens the geographic load for reviews, too.

And remove Kevin since his departure from the team.