Adding the ability to skip updating the PR with a comment.

We've felt the need to be able to override the default comment on pull requests and modified the ghpr plugin. Please let us know what we can do to get this merged.
That's odd, in the fork we cloned, version 1.13-SNAPSHOT was actually changed by you valdis, see: https://github.com/joelj-taulia/ghprb-plugin/commit/8994595b4239747ad7c5b0be1ff3ef53d2f29b15