Fix typo in set_context call when computing sale cash rounded amounts

Closes #12800
(grafted from 84648680b6ff1815083178a9b7be8c4415f7b1ac)

--HG--
branch : 7.0

modules/account_cash_rounding/sale.py

@@ -45,7 +45,7 @@ class Sale(metaclass=PoolMeta):
         if self.currency:
             amounts = [amount]
             if self.payment_term and self.company:
-                with Transaction().set_company(company=self.company.id):
+                with Transaction().set_context(company=self.company.id):
                     today = Date.today()
                 try:
                     term_lines = self.payment_term.compute(