title: Conversion of string to array in jolt transformation
body: <p>I have a input json like this:</p>
  
  <p>Input:</p>
  
  <pre class="lang-js prettyprint-override"><code>{
       "userstatus": {
           "authtype": "S,R,T",
       }
  }
  </code></pre>
  
  <p>Here i need to change for the key - authtype and put those values into an array .</p>
  
  <p>Expected Json:</p>
  
  <pre><code>{
      "userstatus": {
          "authtype": ["S","R","T"]
      }
  }
  </code></pre>
  
  <p>But actual Output i got like this:</p>
  
  <pre><code>{
      "authtype" : [ "S,R,T" ]
  }
  </code></pre>
  
  <p>JOLT SPEC:</p>
  
  <pre><code>[
      {
          "operation": "shift",
          "spec": {
              "userstatus": {
                  "authtype": "authtype.[]"
              }
          }
      }
  ]
  </code></pre>
  
  <p>Please help me for the above test case?</p>