CLI command 'apps:create --stack cedar' is now deprecated

Change effective on 11 August 2023

When the Cedar stack reached end-of-life, the --stack cedar option in a heroku apps:create command was changed to create an app on the latest default stack instead of Cedar.

For consistency with all other possible values for --stack, this will now fail with an unsupported stack error:

$ heroku apps:create --stack cedar
Creating app... !
 ▸    Creating new apps on the cedar stack is not supported. Please consider using heroku-22 instead:

Customers targeting a particular stack are advised to specify this stack explicitly using --stack. Omitting the --stack option during app creation will always cause the latest default stack to be used.