JSON Schema no longer works since jsonix.org is offline

Hey team,

Looks like when converting to JSON Schema, all the types do not use primitives, but rather refer to an external schema hosted on jsonix.org.

Example:
```json
{
"$ref":"http://www.jsonix.org/jsonschemas/w3c/2001/XMLSchema.jsonschema#/definitions/dateTime"
}
```

This site appears to have gone offline, rendering these schemas useless.

Wondering:
- is this intentional?
- are these available on GitHub?

Seeking advice