RFR: 253: Add note about git-publish to README

[Robin Westberg]

On Mon, 3 Feb 2020 10:22:56 GMT, Erik Helin <ehelin at openjdk.org> wrote:

> Hi all,
> 
> please review this small patch that updates the README with some info about
> `git-publish`.
> 
> Thanks,
> Erik

Looks good, thanks for fixing!

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Marked as reviewed by rwestberg (Reviewer).

PR: https://git.openjdk.java.net/skara/pull/390