pos/pos_quick_logout/views/assets.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
    Copyright (C) 2016-Today: La Louve (<http://www.lalouve.net/>)
    @author: Sylvain LE GAL (https://twitter.com/legalsylvain)
    License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
-->

<odoo>

    <template id="assets_frontend" inherit_id="point_of_sale.assets">
        <xpath expr="." position="inside">
            <script type="text/javascript"
                src="/pos_quick_logout/static/src/js/pos_quick_logout.js"/>
        </xpath>
        <xpath expr="//link[@id='pos-stylesheet']" position="after">
            <link rel="stylesheet"
                href="/pos_quick_logout/static/src/css/pos_quick_logout.css" />
        </xpath>
    </template>

</odoo>