title: how to pass multi value query params in swagger
body: <p>I have following service in swagger.yml. The service is written so that page_id can be passed multiple times. e.g <code>/pages?page_id[]=123&amp;page_id[]=542</code></p>
  
  <p>I checked this link <a href="https://swagger.io/specification/" rel="noreferrer">https://swagger.io/specification/</a> but couldnt understand how could i update yml so i could pass id multiple times.</p>
  
  <p>I see that i have to set <code>collectionFormat</code> but dont know how.</p>
  
  <p>I tried updating it like below but no luck <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md" rel="noreferrer">https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md</a>. </p>
  
  <p>it generates url like '<a href="http://localhost:0000/pages?page_id=123%2C%20542" rel="noreferrer">http://localhost:0000/pages?page_id=123%2C%20542</a>`</p>
  
  <pre><code> '/pages':
      get:
        tags:
          - 
        summary: get the list of pages
        operationId: getPages
        produces:
          - application/json
        parameters:
          - name: page_id
            in: query
            description: some description
            required: false
            type: string
            collectionFormat: multi
          - name: page_detail
            in: query
            description: some description
            required: false
            type: string
        responses:
          '200':
            description: OK
          '401':
            description: Authentication Failed
          '404':
            description: Not Found
          '503':
            description: Service Not Available
  </code></pre>