Changing your email address is indeed a bit messy right now, since we’re still in the process of migrating account management from our old V2 Account Server to our new “The Things ID” system.
If you go to https://account.thethingsnetwork.org/, you should be able to change your email address. The next time you sign in to The Things Stack Community Edition, it should update your email address.
cc: @adrianmares