asset download should give !=0 returncode when no assets found/other error happens

[jupe]

Tool should return non success return code when asset download fails or no assets found with used PATTERN. This would simplify/help scripting..

[lyoshenka]

Agreed. I use githubrelease as part of CI and if it doesn't return an error code when the asset is not found, the CI system won't know that something went wrong.