App(Beta) - DeploymentError when you run app.Update while app status is Deploying

[lambdaR]

I think it is worth checking first if the app's status is Running before sending a command (Update) to the provider, not doing the check will leads to a DeploymentError.

[asim]

I've fixed this so it returns an error saying it's already deploying. Ideally we'd queue updates or something but maybe that's a future thing.