Environment Deployment - Project/Branch Locking

I like how we can specify that a certain environment can only have certain projects deployed to it, but it'd be even nicer to take this one step further and lock down what branch(es) are allowed to be deployed as well.

We do a good job of managing that in our AppVeyor.yml files for automated builds, however, on one occasion a member of our team accidentally deployed the wrong branch to production via a manual deploy.

This was quickly fixed but it'd be nice to block that from happening.

Thanks!