[MIG] account_banking_sepa_direct_debit: Finish migration to 12.0

* Fixed tests
* Adjust code for Python dates handling
* Update copyrights

account_payment_order/models/account_move_line.py

@@ -43,6 +43,9 @@ class AccountMoveLine(models.Model):
                         self.invoice_id.type in ('in_invoice', 'in_refund') and
                         self.invoice_id.reference):
                     communication = self.invoice_id.reference
+                elif 'out' in self.invoice_id.type:
+                    # Force to only put invoice number here
+                    communication = self.invoice_id.number
         if self.currency_id:
             currency_id = self.currency_id.id
             amount_currency = self.amount_residual_currency