[FIX] point_of_sale: fix point of sale sequence declaration, github issue #3218

addons/point_of_sale/point_of_sale_sequence.xml

@@ -36,7 +36,7 @@
     <record model="ir.sequence" id="seq_pos_session">
         <field name="name">POS Session</field>
         <field name="code">pos.session</field>
-        <field name="prefix">POS/%(day)s/(month)s/%(year)s/</field>
+        <field name="prefix">POS/%(day)s/%(month)s/%(year)s/</field>
         <field name="padding">4</field>
     </record>