RFR: git-pr: use commit message from most recent commit

[Robin Westberg]

On Tue, 24 Mar 2020 12:37:33 GMT, Erik Helin <ehelin at openjdk.org> wrote:

> Hi all,
> 
> please review this patch that ensure that `git pr create` always use the subject
> from the most recent commit as the title for the pull request. Furthermore
> `git pr create` will now also require a body for the pull request to be present.
> 
> Testing:
> - Manual testing of `git pr create` on Linux x64
> 
> Thanks,
> Erik

Looks good!

-------------

Marked as reviewed by rwestberg (Reviewer).

PR: https://git.openjdk.java.net/skara/pull/537