"work in progress" now supported for pull requests

You know how sometimes you want to get a pull request out there so
people know you're actually working on something, but you don't want
the bot hassling you about it?

Well, now you can just prepend [WIP] to the title of your pull
request, and the Ansibull-bot will just give it the "work_in_progress"
label and leave it alone. When you decide you're ready to proceed with
an actual review, just remove [WIP] from the title, and the bot will
take care of the rest.

(Works in module-core and module-extras repos only.)

Thanks @resmo for the PR. :slight_smile:

--g