Compose action payloads with utility functions

You can now compose action payloads with utility functions to ease JSON escaping, URL encoding, and Base64 encoding. If custom content within the JSON formatted parameters template is a JSON structure in itself, it needs to be escaped - this can now be achieved right within the template so that JSON content can simply be pasted from other sources for example:

{
  "FunctionName": "arn:aws:lambda:ap-southeast-2:123456789012:function:sample-AutomationWithAWSQuickstartLamb-1RRX37PWXZXLS",
  "Payload": "$util.escapeJson('{
      "Event":"$event.simpleName",
      "Timestamp": "$event.timestamp",
      "TraceID": "$event.traceId"
    }')"
}