Warning 'a promise was rejected with a non-error' for external queues in case of an error.

Created by: jpschober

Description

If you run a bull queue as external process you get a bluebird warning in case of an error about a promise that was rejected with a non-error. This is due to the sandbox implementation that rejects simply with an error message as string.

I will create a pull request for this. Happy to hear if that one is OK.

Bull version

3.3.10