Codegen fails with a `not implemented yet` panic for object with `format: date`

This is the API spec I was trying to generate code for: https://docs.finix.com/_spec/api/index.yaml

This is the error I get:

progenitor::generate_api!("finix.yaml");
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: message: not yet implemented: invalid (or unexpected) schema:
          {
            "description": "The principal control owner's date of birth.",
            "type": "object",
            "format": "date",
            "properties": {
              "day": {
                "description": "Day of birth (between 1 and 31).",
                "type": "integer"
              },
              "month": {
                "description": "Month of birth (between 1 and 12).",
                "type": "integer"
              },
              "year": {
                "description": "Year of birth (4-digit).",
                "type": "integer"
              }
            }
          }

Start with the progenitor::generate_api!("finix.yaml") entry point and reproduce the panic using the linked Finix API specification. Trace how the object schema with format: date is classified, then establish expected generation behavior and verify that code generation completes without the not implemented yet panic.