Based on https://www.agenciatributaria.es/AEAT.internet/Inicio/La_Agencia_Tributaria/Campanas/Retenciones/Cuadro_informativo_tipos_de_retencion_aplicables__2020_.shtml closes odoo/odoo#55851 X-original-commit: 41ac6df5e8483111c5ec33e89c65b6c60b26b81e Signed-off-by: Josse Colpaert <jco@openerp.com>