Nullable<string> on required:true

[dara-rockwell]

KEY: {
    required: true
}

• Typescript is complaining that the type is still Nullable<string> instead of string
• It appears that autoConfig is trying to figure out what the type is based upon default, but if there is no default then it presumes it can be Nullable even thought required is set to `true.

When running tests, at runtime we receive the following error as well:

ERROR: Found 1 Config Problem(s)!

    Fix the following 1 issue(s). (tip: try '--help' output for more details.)

      - Required: KEY invalid_type

This error is resolved by adding default: '' to the config

[dara-rockwell]

@justsml Any chance we can get a fix for this?