Invoice items

curl --request GET \
     --url 'https://www.zep-online.de/zepinstanz/next/api/v1/invoices/20240001/items' \
     --header 'Accept: application/json' \
     --header 'Authorization: Bearer {token}'

{
	"data": [
        {
            "id": 97,
            "project_id": 1,
            "customer_number": "10001",
            "from": null,
            "to": null,
            "repetition": null,
            "quantity": "1.00000",
            "unit_price": "815.0000",
            "unit": null,
            "currency": "EUR",
            "language": "de",
            "status": {
                "id": 2,
                "name": "Billed"
            },
            "kind": {
                "id": 1,
                "name": "Flat Rate"
            },
            "type": {
                "id": 0,
                "name": "Geplante"
            },
            "invoice_number": "20240001",
            "invoice_text": "",
            "sorting": "1",
            "contains_working_hours": null,
            "contains_receipts": null,
            "contains_travel_expenses": null,
            "planned_amount": null,
            "planned_date": "2024-05-31T00:00:00.000000Z",
            "billed_amount": "815.00",
            "billed_date": "2024-05-31T00:00:00.000000Z",
            "vat": "19.0000",
            "project_task_id": 100,
            "ticket_id": null,
            "article_id": null
        }
	]
}