[FIX] website_sale_secondary_unit: Adjust to upstream changes

As the product.secondary.unit view has been isolated, we have to
inherit from that one.

website_sale_secondary_unit/views/product_secondary_unit_views.xml

@@ -1,12 +1,13 @@
 <?xml version="1.0" encoding="utf-8" ?>
 <!-- Copyright 2019 Tecnativa - Sergio Teruel
+     Copyright 2021 Tecnativa - Pedro M. Baeza
      License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl). -->
 <odoo>
-    <record id="product_template_website_publish_form_view" model="ir.ui.view">
-        <field name="model">product.template</field>
+    <record id="product_secondary_unit_view_tree" model="ir.ui.view">
+        <field name="model">product.secondary.unit</field>
         <field
             name="inherit_id"
-            ref="product_secondary_unit.product_template_form_view"
+            ref="product_secondary_unit.product_secondary_unit_view_tree"
         />
         <field name="arch" type="xml">
             <field name="factor" position="after">