For Failed PRs, add labels for common errors

[jamesfwood]

To make it easy to see why a PR is failing, add some common labels.

Example:

• "Unable to download" (Forbidden or 404, or 500 error) (tests skipped label now i think?)
• "Umm-v issue" (no umm-v associated, or lat/lon issue)
• "No granules"
• "Eula issue"
• and any more common ones

This was requested by a DAAC as well. I think it was OB DAAC.