message: Add CosmosDBMongo enum
diff: "type": "string",
  "enum": [
  "CosmosDBCassandra",
  + "CosmosDBMongo",
  "CosmosDBSql",
  "AzureBlobStorage"
  ],
  ],
  "x-ms-discriminator-value": "CosmosDBCassandra"
  },
  + "CosmosMongoDataTransferDataSourceSink": {
  + "type": "object",
  + "description": "A CosmosDB Cassandra API data source/sink",
  + "properties": {
  + "databaseName": {
  + "type": "string"
  + },
  + "collectionName": {
  + "type": "string"
  + }
  + },
  + "allOf": [
  + {
  + "$ref": "#/definitions/DataTransferDataSourceSink"
  + }
  + ],
  + "required": [
  + "databaseName",
  + "collectionName"
  + ],
  + "x-ms-discriminator-value": "CosmosDBMongo"
  + },
  "CosmosSqlDataTransferDataSourceSink": {
  "type": "object",
  "description": "A CosmosDB Cassandra API data source/sink",
  