header field in json report message?

[olavtenbosch]

To identify the version of the schema being used, maybe add a header part with a reference?. Suggestion:

{
"header": {
"$schema": "https://raw.githubusercontent.com/data-cleaning/ValidatReport/master/json/validation_report.json",
"prepared": "2017-10-24T03:30:00"
}
[
.. // here the validation events
]
}