RFR: 975: Add /open pull request command

[Robin Westberg]

On Sat, 17 Apr 2021 09:23:33 GMT, Erik Helin <ehelin at openjdk.org> wrote:

> Hi all,
> 
> please review this patch that adds the `/open` pull request command to allow pull request authors to re-open a closed pull request.
> 
> Thanks,
> Erik

Looks good!

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Marked as reviewed by rwestberg (Reviewer).

PR: https://git.openjdk.java.net/skara/pull/1123