Ability to use array type drf-compound-fields ListField

When ListField from drf-compound-fields is used it represents it self as a "field". Subclassing and specifying ListField.type_label = array will case it to be properly displayed as array type

    from drf_compound_fields.fields import ListField

    class ListField(ListField):
        type_label = 'array'
        type_name = 'ListField'