Feature idea: post comment with errors if there are any

[kubukoz]

This probably needs a reasonable heuristic to minimize the size of the comments (e.g. last N characters according to github's/gitlab's comment length limit), but it would be great if Steward posted a comment if the build fails, with some relevant lines.

How hard would that be to find errors in the logs? I assume posting the comment is the easy part, since it's already being done on superseding PRs.

[nafg]

Even just opening a ticket "Scala steward can't run" would be helpful. Explanation why would be better of course.

And "will try again in a week." (Frank just mentioned on a different issue that it skips broken builds for a week.)

Actually I just had a different idea. It could use ticket state as a heuristic: if the ticket is still open don't bother trying again even after a week. When the ticket is closed, that means it should retry (perhaps with some minimum to avoid abuse). Or, it could be triggered by commenting on the ticket something like "@scala-steward retry" and if it succeeds then it will close the ticket automatically.