Change email address for account

It's been a couple of years since I played (I know - what the heck was I thinking!) and the email address I use of different from what my desktopdungeons.net account is set to and that is linked to my Steam account.
How do I change the email address for my desktopdungeons.net account?
How do I change the email address for my desktopdungeons.net account?