[Rev 01] RFR: git-pr: support git pr create --draft

[Erik Helin]

On Tue, 18 Feb 2020 15:25:53 GMT, Robin Westberg <rwestberg at openjdk.org> wrote:

>> The pull request has been updated with 1 additional commit.
> 
> Looks good!

Just pushed a new commit that also enables the command `git pr set --no-draft` in order to support moving a PR in draft state to a non-draft state. The GitHub API for doing so was only available in the GraphQL API, so I had to add a new `RestRequest` to `GitHubHost`. It makes sense for the GraphQL `RestRequest` to be a field in `GitHubHost` since all GraphQL requests use the same [endpoint](https://api.github.com/graphql).

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

PR: https://git.openjdk.java.net/skara/pull/454