[BUG][Go][Server] File upload does not seems to work

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Defining requestBody as a media file generate invalid code that use *os.File{}.

This is not possible to work with file upload as the code is not correct.

openapi-generator version

6.0.0-SNAPSHOT

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  description: Test
  title: Test
  version: 0.0.0
servers:
- url: http://127.0.0.1:8080/api/v1
tags:
- description: Videos operations
  name: videos
paths:
  /videos:
    post:
      description: Create a video
      operationId: createVideo
      requestBody:
        content:
          videos/*:
            schema:
              format: binary
              type: string
        description: Video to add
        required: true
      responses:
        "201":
          description: Null response
        default:
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
          description: Unexpected error
      summary: Create a video
      tags:
      - videos
components:
  schemas:
    Error:
      properties:
        code:
          format: int32
          type: integer
        message:
          type: string
      required:
      - code
      - message
      type: object

Generation Details

Steps to reproduce

docker run --rm -v "${PWD}:/local" openapitools/openapi-generator-cli generate \
    -i /local/openapi.yaml \
    -g go-server \
    -o /local/server \
    --additional-properties=packageName=testapi,featureCORS=true,sourceFolder=testapi

Related issues/PRs

Suggest a fix

I have tried to change *os.File{} to *os.Create("tmp") but this lead to another error during the Decode step.

Start by running the supplied docker openapi-generator command with the provided OpenAPI declaration and inspect the generated go-server file-upload handling. Trace the Decode step and determine why the generated code uses *os.File{}; done means the generated server accepts the binary request body without invalid code or a subsequent Decode error.