[Spring] OpenApi 3 File upload issue

Description

Spring generated code for a openapi3 file upload wants a java.io.File for the parameter. In swagger 2 it generates a MultipartFile. The issue with this is when i curl a request to the server, spring reads the request and makes a MultipartFile and the request fails.

Swagger-codegen version

Used version 3.0.3 and 3.0.4-SNAPSHOT

Swagger declaration file content or url

Open Api 3 example yml

openapi: 3.0.2
info:
  description: Api Documentation for the Test service
  version: '2.0'
  title: Test Service
tags:
  - name: Test
    description: Test
paths:
  /Test:
    post:
      tags:
        - Test
      summary: Create the specified file
      operationId: createfile
      requestBody:
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                orderId:
                  $ref: '#/components/schemas/metadataDto'
                fileName:
                  type: string
                  format: binary
      responses:
        '201':
          description: Successfuly created
        '401':
          description: Unauthorized
        '403':
          description: Forbidden
components:
  schemas:
    metadataDto:
      type: object
      properties:
        thing:
          type: string
        thing2:
          type: string

Swagger 2 file

tags:
  - name: Testservice
info:
  version: 0.0.0
  title: title
  description: description
  termsOfService: terms
paths:
  /test/:
    post:
      tags:
        - Testservice
      consumes:
        - multipart/form-data
      parameters:
        - name: file
          in: formData
          required: true
          type: file
        - name: thing
          in: query
          required: false
          type: string
        - name: thing2
          in: query
          required: false
          type: string
      responses:
        '200':
          description: successful operation

Command line used for generation

java -jar swagger-codegen-cli-3.0.3.jar generate -i swagger2.yml -l spring -o srcDir

Steps to reproduce

Generate the spring server code.
Start the server
Curl the server with a file and object and the request will fail

Related issues/PRs

Suggest a fix/enhancement

Start with the spring server generation path invoked by swagger-codegen-cli with -l spring, then reproduce the OpenAPI 3 multipart/form-data example by generating and running the server. Compare the generated upload parameter handling with the Swagger 2 example; done means a curl request containing the file and object is accepted successfully.