fix: detect run failure

[jdbruijn]

This build succeeded when I think it should have failed due to the Renovate warning. Let's see whether we can do something like warnings as errors for our test runs.

https://github.com/renovatebot/github-action/runs/654100781?check_suite_focus=true

[viceice]

maybe can let renovate write the json log file and after run we parse it for known error written as debug and fail out ci if such errors are found

[DanielHabenicht]

This would be pretty neat: https://docs.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-a-warning-message