More Hooks for Pull Request Integrations

It would be nice to have a way to hook into when pull requests are created / updated via an sdk hook or by other means. Our business case for this is that we want to integrate a build solution into PR's so that we can have them build when PR's are created / updated. From our current reading the only way to do this is to tap into the PR update hook which is triggered when someone visits a PR and the merge is kicked off in the background. Looking online yields no good clean solutions and this is something that github already does very well.