[FIX] project: make project_ids field required

When we create a project stage (project task type),
it is essential that we link it to a project.

Otherwise, the record created will never be accessible.

opw-3322992

closes odoo#122614

Signed-off-by: Xavier Bol (xbo) <xbo@odoo.com>

addons/project/views/project_views.xml

@@ -128,7 +128,7 @@
                             <group>
                                 <field name="fold"/>
                                 <field name="is_closed" groups="base.group_no_one"/>
-                                <field name="project_ids" widget="many2many_tags" options="{'color_field': 'color'}" groups="base.group_no_one"/>
+                                <field name="project_ids" widget="many2many_tags" options="{'color_field': 'color'}" required="1"/>
                             </group>
                         </group>
                         <group string="Stage Description and Tooltips">