message: Add 'preview' to versionKind enum
diff: "readOnly": true,
  "enum": [
  "Latest",
  - "Previous"
  + "Previous",
  + "Preview"
  ],
  "x-ms-enum": {
  "name": "versionKind",
  },
  {
  "value": "Previous"
  + },
  + {
  + "value": "Preview"
  }
  ]
  }
  