RFR: git-pr-fetch: remove --branch option

[Robin Westberg]

On Sat, 5 Sep 2020 07:20:00 GMT, Erik Helin <ehelin at openjdk.org> wrote:

> Hi all,
> 
> please review this patch that removes the `--branch` option from `git pr fetch` to make `git pr fetch` align better
> with `git fetch`.
> Thanks,
> Erik

Looks fine!

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Marked as reviewed by rwestberg (Reviewer).

PR: https://git.openjdk.java.net/skara/pull/793