Publish testcraft from PRs to relevant branches #982
Description
What needs to get done
Once we have completed canonical/craft-actions#48
Use that action to publish the testcraft snap to the latest/edge/craft-application-<pr#> branch.
Running on main should publish to the latest/edge/craft-application-main branch. NOTHING should release directly to any public channels.
When running from a PR, this workflow should also make a comment notifying that the snap has been released. This should include both snap install and snapcraft refresh --amend commands for easy copy/paste.
Why it needs to get done
Make it far easier for reviewers to test changes in a real-world situation.