Environment Promotion

I have a preview branch that I use to auto deploy to my staging environment every time I merge a PR to the preview branch. After I test in preview I want to promote the code to production, the way I do that today is by merging a deploy PR into main with the changes. There is the automatic creation of environments based on PR's but I want the preview environment to have a static url so creating ephemeral services wont work for this use case.