erp5_payzen_secure_payment: Convert boolean to 1 or 0 on Payzen

According to Payzen API, boolean should be translated into 0 or 1 in order to be part of the signature.
The only value which contains a boolean is "litige" which can cause signature miss-match without
this change.

bt5/erp5_payzen_secure_payment/DocumentTemplateItem/portal_components/document.erp5.PayzenService.py

@@ -303,6 +303,8 @@ class PayzenService(XMLObject, PayzenSOAP):
       elif isinstance(v, datetime.datetime):
         # for sure date
         v = v.strftime('%Y%m%d')
+      elif isinstance(v, bool):
+        v = str(int(v))
       else:
         # anything else cast to string
         v = str(v)