OpenAPI 3.0.3 documentation with RSwag Unable to Send "Content-Type" header

Question

For my Rails project I am using RSwag to generate documentation using OpenAPI 3.0.3 specifications.

I know with Open API 3.0.3 'If in is "header" and the name field is "Accept", "Content-Type" or "Authorization", the parameter definition SHALL be ignored.'

However I know they can be generated by configuring the rspec and swagger_helper.rb files properly. For example, my swagger_helper.rb has

  config.swagger_docs = {
    'v1/swagger.json' => {
      openapi: '3.0.3',
      info: {
        title: 'My company API',
        version: 'v1'
      },
      servers: [
        {
          url: "#{ENV['PROTOCOL']}://#{ENV['BINDING']}:#{ENV['PORT']}"
        }
      ],
      components: {
        contentType: 'application/vnd.api+json',
        headers: {
          contentType: {
            description: "content type",
            schema: {
              type: :string
            }
          }
        },
        securitySchemes: {
          authorization_header: {
            type: :apiKey,
            name: 'Authorization',
            in: :header,
            description: "Expected format: app_name:api_key"
          }
        },
        schemas: {
          errors_list: {
            "$schema": "http://json-schema.org/draft-04/schema#",
            "type": "object",
            "properties": {
              "errors": {
                "type": "array",
                "items": [
                  {}
                ]
              }
            },
            "required": [
              "errors"
            ]
          }
        }
      },
      encoding: {
        contentType: 'application/vnd.v1+json'
      },
      mediaType: {
        schema: {
          type: :string
        },
        example: 'application/vnd.v1+json',
        encoding: {
          contentType: 'application/vnd.v1+json'
        }
      }
    }
  }

and one of my rspec file has

path '/api/segments/{id}', swagger_doc: 'v1/swagger.json' do
    get 'Show segment by id' do
      after do |example|
        example.metadata[:response][:content] = { 'application/json' => JSON.parse(response.body, symbolize_names: true) }
      end
      let(:segment) { create(:segment, user: user) }
      let(:id) { segment.id }
      let(:Authorization) { auth_header }
      produces 'application/vnd.my_company.v1+json'
      consumes 'application/vnd.api+json'
      security [ authorization_header: [] ]
      tags :segments
      parameter name: :Accept, in: :header, type: :string, required: true, example: 'application/vnd.my_company.v1+json'
      parameter name: 'Content-Type', in: :header, type: :string, required: true, example: 'application/vnd.api+json'
      parameter name: :Authorization, in: :header, type: :string, required: true
      parameter name: :id, in: :path, type: :integer , required: true, description: 'id of segment'
      parameter name: :marketplace, in: :query, type: :string, schema: { type: :string }, required: true, description: 'marketplace of segment'
     context 'abc' do
        response '200', :success do
          run_test! do |response|
           xxxx
          end
        end
     end
end

With the definitions for securitySchemes and using it with security [ authorization_header: [] ], as well as using produces 'application/vnd.my_company.v1+json', I am able to send Authorization and Accept headers on my swagger UI page using the "Try it out" functionality.

However, I am not able to send the Content-Type header. Where did I do wrong?

I know if I use Swagger 2.0 instead of OpenAPI 3.0.3 this problem will not occur, but I don't want to switch.

Update:

I manually added:

"requestBody": {
          "content": {
            "application/vnd.api+json": {}
          }
        },

underneath

  "paths": {
    "/api/segments/{id}": {
      "get": {
        "summary": "Show segment by id",
        "security": [
          {
            "authorization_header": [

            ]
          }
        ],
        "tags": [
          "segments"
        ],
        "requestBody": {
          "content": {
            "application/vnd.api+json": {}
          }
        },

in my swagger.json file and now it lets me send Content-Type header!

But how do I do it in my swagger_helper.rb or the rspec file?

Thank you!