Oh no, not another "antivirus" program as well.
This happened/happens with Norton as well, see here. Of course, WorkingHours does not contain a virus. A heuristic detection doesn't mean that a file is infected. The antivirus app just "thinks" that because of certain information (maybe because the file ending is .exe).
I suspect that those programs are not familiar with apps being built with Xamarin (a cross-platform technology by Microsoft) and that Xamarin apps are behaving in a way different than "normal" macOS apps built with Objective-C or Swift and that this makes these errors to show up.
I don't know how to "prove" that WorkingHours does not contain any virus. False-positives like this happen, from my experience especially those "heuristic" false-positives.