title: elasticsearch update gives unknown field error
body: <p>I am using the Elasticsearch's Typescript client, and when I try to update a document:</p>
  
  <pre><code>import { RequestParams } from '@elastic/elasticsearch'      
  const updateParam: RequestParams.Update = {
        id: '111',
        index: 'myIndex',
        body: {email: 'aaa@aa.ca'},
  }
  return elasticsearchClient.update(updateParam)
  </code></pre>
  
  <p>I am getting an error saying:</p>
  
  <pre><code>{
      "error": {
          "root_cause": [
              {
                  "type": "x_content_parse_exception",
                  "reason": "[1:2] [UpdateRequest] unknown field [id], parser not found"
              }
          ],
          "type": "x_content_parse_exception",
          "reason": "[1:2] [UpdateRequest] unknown field [id], parser not found"
      },
      "status": 400
  }
  </code></pre>
  
  <p>But according to the document here: <a href="https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/api-reference.html#_update" rel="noreferrer">https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/api-reference.html#_update</a>, <code>id</code> is a field in the input</p>
  
  <p>What's wrong with my request param?</p>