web_techsystech/web_widget_numeric_step/demo/ir_cron.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <record id="ir_cron_view_form" model="ir.ui.view">
        <field name="model">ir.cron</field>
        <field name="inherit_id" ref="base.ir_cron_view_form" />
        <field name="arch" type="xml">
            <field name="interval_number" position="attributes">
                <attribute name="widget">numeric_step</attribute>
                <attribute name="options">{'step': 2, 'min': 0, 'max': 40}</attribute>
            </field>
        </field>
    </record>
</odoo>