Provide validation / warning deployment logs to the user for temporary deploys (diffs)

[paulRbr]

When a user uses the diff feature of the GH action, if may happen that we add warning deployment logs (due to an incorrect input API document, or something we've detected during diff computation). Some logs are not visible to the user because the deployed versions are temporary (and not visible in their Bump.sh workspace).

A potential solution could be to display warning deployment logs in the Github Action comment published on PRs.

Feel free to suggest other solutions in this issue if you have other ideas (it could be stronger validation before the deployment, see bump-sh/cli#5, which could be in a separate workflow step in the CI)