Publish Extension to ADS marketplace on new release

[SteveL-MSFT]

Summary of the new feature

As part of our release process, we should be able to leverage AzDevOps pipelines to auto-publish to ADS marketplace (creating a PR to update their extension) whenever we publish a new stable release.

[andyleejordan]

Whoops, thought this was to the general VS Code marketplace, which we need to do first. Then we can do the ADS marketplace (however, it may always be manual because they need to verify version support before taking new releases).

[andyleejordan]

It is indeed always going to be manual, they have to verifyy updates. I suggested we could automate opening an issue for them every time we ship a new stable version, but they opted not to take us up on that and instead will just check for the latest version from our releases page on GitHub each time they go to make a new ADS release.