Enable yaml stages based publishing

[ViktorHofer]

https://github.com/dotnet/arcade/blob/master/Documentation/YamlStagesRepoStatus.md. Target completion data is 8/13.

We need to do this sooner than later.

cc @safern @wtgodbe @ericstj

[ericstj]

Yeah, @joperezr and @safern were discussing doing this yesterday.

[safern]

Yeah I already started looking at this yesterday.