People are busy and your audience may totally appreciate the brevity.
Once again, this is up to you. Just make sure that you’re not dragging things out. There is nothing wrong with having a 5 minute long episode. People are busy and your audience may totally appreciate the brevity. Beware of simply copying others and trying to fill time just to fill it. If you bring on a guest and the conversation is done after 20 minutes, let it be done. Make your episodes as long or short as they need to be, and not a minute longer.