title: Appsync response mapping template json key name change
body: <p>What would be the right way to change json response key value in aws appsync response mapping template?</p>
  
  <p>JSON that I get looks like this:</p>
  
  <pre><code>{
    "tenant_id": 1,
    "id": "bd8ce6a8-8532-47ec-8b7f-dcd1f1603320",
    "header": "Header name",
    "visible": true
  }
  </code></pre>
  
  <p>and what I would like to pass forward is</p>
  
  <pre><code>{
    "tenantId": 1,
    "id": "bd8ce6a8-8532-47ec-8b7f-dcd1f1603320",
    "header": "Header name",
    "visible": true
  }
  </code></pre>
  
  <p>Schema wants tenant id in form of tenantID and lambda returns it in form of tenant_id. I could change it in lambda but I would like to know how to do it in response mapping template.</p>