[FIX] purchase: set date_approve as now when approve
[FIX] purchase: set date_approve as now when approve

685f4eff507e126832b0ba01c8392f1777540dac added date_approved as
fields.Date.context_today
b5cea7e2b6908c5c8ab051f296e5e4c85e64c9fe has changed the field
as a Datetime

Both together introduced a miss calculation of the date_approved

closes odoo/odoo#48055

X-original-commit: 6dff3024d19c9dd44c71992469540e3f09dd3247
Signed-off-by: Denis Ledoux (dle) <8dd417b68ca1b41b9fae61f535fe0b5d847bdd55@odoo.com>

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo