Passing a string value to delay fails silently

Created by: sarincasm

Description

This is a minor defect. When creating a delayed job, if delay option is passed as a string, the job gets added but never gets executed, nor does it throw any error.

Minimal, Working Test code to reproduce the issue.

Add a job - This gets added, doesn't throw but never gets executed

		myQueue.add(
			data,
			{delay: '1200'}
		)

Simply doing this works fine:

		myQueue.add(
			data,
			{delay:  parseInt('1200')}
		)

Bull version

3.4.8