Unable to upgrade project to config v3

Hi, I'm trying to set up migrations so that they can be controlled through version control. currently, I'm following this documentation https://hasura.io/docs/latest/graphql/core/migrations/migrations-setup.html. My schema doesn't have `default` database so, i had to upgrade to config v3. while running this command `hasura scripts update-project-v3` i get
```
FATA[0063] {
"path": "$",
"error": "source with name \"default\" does not exist",
"code": "not-exists"
}
```

I'm confused about what I'm doing wrong. how can I get rid of this?

Start with the migrations setup documentation and reproduce the `hasura scripts update-project-v3` command using a project whose schema has no `default` database. Trace how the command handles the reported missing `default` source; done means the project upgrades successfully or reports a clear, actionable requirement for the configured database source.

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