The newly added `pulumi config refresh` updates your local copy of the
Pulumi.<stack-name>.yaml file to have the same configuration as the
most recent deployment in the cloud.
This can be used in a varirty of ways. One place we plan to use it is
in automation to clean up "leaked" stacks we have in CI. With the
changes you'll now be able to do the following:
```
$ cd $(mktemp -d)
$ echo -e "name: who-cares\nruntime: nodejs" > Pulumi.yaml
$ pulumi stack select <leaked-stack-name>
$ pulumi config refresh -f
$ pulumi destroy --force
```
Having a simpler gesture for the above is something we'll want to do
long term (we should be able to support `pulumi destory <stack-name>`
from a completely empty folder, today you need a Pulumi.yaml file
present, even if the contents don't matter).
But this gets us a little closer to where we want to be and introduces
a helpful primitive in the system.
Contributes to #814
6845f9ed20