On PR, release charm to temporary branch pr/edge/N #400
Description
The pack-charm job uploads the built charm(s) as an artifact of the workflow. This is handy, because we can parallelize the integration tests without rebuilding the charm every time - we just download the artifact.
What we should do in addition to uploading the artifact is to release the same charm(s) to a temporary branch on charmhub. We can have a dedicated track for it, and only use edge, i.e. charmcraft upload --release to pr/edge/N, where N is the PR number.
If the upload to charmhub fails for some reason, it shouldn't fail the rest of the workflow, because the workflow depends on the artifact (we currently don't want the workflow to depend on deploying the charm from charmhub).
If a PR is contributed by someone outside the org, the workflow should be manually approved by a maintainer, and then released to a PR branch just the same.