[BUG][Swift] String / Byte array gets mapped to Data instead of String in Model

Description

I have a property in my Open API specifications that is defined as a byte array. In the Model that is generated for Swift this is mapped to a Data type instead of a String type.

And this wouldn't be too big of a deal, since I should be able in Swift to convert a Data object to a String, but for some reason if I do that the encoding gets all messed up. So this might even be a totally different issue. But what I do know, is that if I manually edit the Model and replace Data with String then everything works fine.

openapi-generator version

• 6.2.1

OpenAPI declaration file content or url

{
  "swagger" : "2.0",
  "info" : {
    "description" : "Example",
    "version" : "v1",
    "title" : "Example",
    "termsOfService" : "None",
    "contact" : {
      "name" : "Foo",
      "url" : "https://www.example.com"
    }
  },
  "host" : "www.example.com",
  "basePath" : "/Example",
  "schemes" : [ "https" ],
  "produces" : [ "application/json" ],
  "paths" : {
    "/api/example" : {
      "get" : {
        "responses" : {
          "200" : {
            "description" : "OK",
            "schema" : {
              "$ref" : "#/definitions/ViewPinProvisionOutput"
            }
          }
        }
      }
    }
  },
  "definitions" : {
    "Example" : {
      "type" : "object",
      "properties" : {
        "signature" : {
          "type" : "string",
          "format" : "byte",
          "pattern" : "^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$"
        }
      }
    }
  }
}

Generation Details

Just generate it the default way:

openapi-generator generate -i example.json -g swift5

Expected Result

The Example struct that is generated should have a property called signature of type String?

Actual Result

The Example struct that is generated has a property called signature of type Data?

Reproduce the issue with the supplied example.json and the openapi-generator generate -i example.json -g swift5 command. Start by tracing how the Swift generator maps a string with format: byte, then add regression coverage for the generated Example model. Done means the signature property is generated as String? without breaking related byte-string handling.