[Swift4] swagger-codegen 3.0.8 and lower create swift models that are incorrectly formatted without line breaks

Description

After enums in a generated model struct there is no line break. This makes the swift compiler throw an error.

Swagger-codegen version

Preoduced issue on 3.0.5 and verified on
swagger-codegen-cli-3.0.8-20190329.080540-4

{
  "title": "ParBlock",
  "type": "object",
  "properties": {
    "type": {
      "title": "Type",
      "default": "seq",
      "enum": [
        "audio",
        "video",
        "sleep"
      ],
      "type": "string"
    },
    "length": {
      "title": "Length",
      "default": 0,
      "type": "integer"
    },
    "name": {
      "title": "Name",
      "default": "",
      "type": "string"
    },
    "par_blocks": {
      "title": "Par_Blocks",
      "default": [
        
      ],
      "type": "array",
      "items": {
        "$ref": "#/components/schemas/Block"
      }
    }
  }
}

Swagger declaration file content or url

Command line used for generation

swagger-codegen generate -i openapi.json -l swift4 -o .

Steps to reproduce

Related issues/PRs

Suggest a fix/enhancement

Reproduce the issue with the supplied schema using the swagger-codegen generate -i openapi.json -l swift4 -o . command. Inspect the generated Swift model around the enum and verify that the output has the required line breaks and compiles successfully.