datev_export_xml length errors

[psc]

Module

datev_export_xml

Describe the bug

In the XML export, the customer reference is output as order_id. However, if the customer reference is > 30 characters, an error is output.

Wrong Data in XML file!
Try to solve the problem with 'INV1234567.xml' according to message below:

Element '{http://xml.datev.de/bedi/tps/invoice/v050}invoice_info', attribute 'order_id': [facet 'maxLength'] The value 'long test value................................................' has a length of '36'; this exceeds the allowed maximum length of '30'., line 3

To Reproduce

Affected versions:
17.0.1.0.1

Steps to reproduce the behavior:
Enter a very long customer reference in the draft invoice, invoice and export to datev xml.

Expected behavior
Cut the customer reference with 30 characters

Additional context
Add any other context about the problem here. (e.g. OS, Python version, ...)