Hi, we did that via the admin function.
- Edit your game in the dashboard.
- In the top right of the navigation you see More
- Then select Admins from the dropdown menu
- Enter the usernames of your team there
- Select Display as contributor?
Now all of your team members are shown as contributors.
As an example our game: https://itch.io/jam/brackeys-3/rate/570492
Both of our names are shown in Submitted by.