Locking r10k deployments

The deploy: write_lock setting allows you to temporarily disallow r10k code deploys without completely removing the r10k configuration.

This setting is useful for preventing r10k deployments at certain times, or for preventing deployments from interfering with a common set of code that might be touched by multiple r10k configurations.

To enable this, add the write_lock setting under the deploy parameter and supply a message that is returned when someone attempts to deploy code. For example:

deploy:
  write_lock: "Deploying code is disallowed until the next maintenance window."