Support for DurationField

[martin-san03]

Hello, I need support for DurationField.

Would be this a valid implementation in converters.py?

@converter
class DurationFieldConverter:
    """
    A converter specifically for Django's DurationField.
    """
    # This attribute tells the registration system which field this handles.
    field_class = serializers.DurationField

    def convert(self, field):
        """
        The method that returns the JSON schema for the field.
        The `field_to_jsonschema` function will automatically add
        the 'title' and 'description' from the field's label and
        help_text afterwards.
        """
        return {
            'type': 'string',
            'format': 'duration',
            # Per ISO 8601 duration format (e.g., "P3DT6H4M")
            'pattern': r'^(\-)?P(?=\d|T\d)(?:(\d+)Y)?(?:(\d+)M)?(?:(\d+)W)?(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d*(\.\d+)?)S)?)?$'
        }

If so, would it be possible to add it to the lib?
Thanks in advance