title: Swagger openapi 3.0.x empty body
body: <p>I am trying to migrate my from swagger 2.0 to openapi 3.0.2 for my express api.
  The swagger definitions and paths are written in swagger-jsdoc. This should cause no problems because their documentation state that it can work with openapi 3.x as well as with swagger 2.0.</p>
  
  <p>When adding openapi: 3.0.x to my swaggerDefinition the views look fine.
  However when trying to do a post request through the swagger views, the body is empty.</p>
  
  <p>My swagger definition looks like this:</p>
  
  <pre><code>const swaggerOptions = {
      swaggerDefinition: {
          openapi: '3.0.2',
          info: {
              title: `Channels API`,
              description: "Channels API",
              version: "v1"
          },
          servers: [ {
              url: "http://127.0.0.1:3000",
              description: 'Local server'
          }],
      },
      apis: ['./routes/*.js'],
  };
  </code></pre>
  
  <p>Now I have a file channels.js as a router:
  It has the following definition in it:</p>
  
  <pre><code>class Channel extends BaseRouter {
  /**
  * @swagger
  *
  * definitions:
  *   channel:
  *     type: object
  *     tags:
  *       - Channels
  *     properties:
  *       name:
  *           type: string
  *       global:
  *           type: boolean
  *     required:
  *       - name
  */
  
  constructor(app, version) {
      super(app, new ChannelCtrl(), version);
  }
  
  post() {
      /**
       * @swagger
       * /api/v1/channels:
       *  post:
       *      tags:
       *          - Channels
       *      name: Create
       *      produces:
       *          - application/json
       *      consumes:
       *          - application/json
       *      summary: Create new channel object
       *      parameters:
       *       - name: channel
       *         required: true
       *         in: body
       *         description: Fields of the channel object to be created
       *         type: object
       *         schema:
       *             $ref: '#/definitions/channel'
       *      responses:
       *          '200':
       *              description: Channel object has been created
       *              application/json:
       *                  schema:
       *                      $ref: '#/definitions/channel'
       */
      this.app.post(`/api/${this.version}/channels`, this.controller.create.bind(this.controller));
      return this;
  }
  </code></pre>
  
  <p>Trying it with swagger 2.0 seems to work fine..
  What am I missing?</p>