cooperative-market/beesdoo_pos/views/beesdoo_pos.xml

<odoo>
    <template id="assets" inherit_id="point_of_sale.assets">
        <xpath expr="." position="inside">
            <script type="text/javascript"
                src="/beesdoo_pos/static/src/js/beesdoo.js"></script>
            <link rel='stylesheet' href="/beesdoo_pos/static/src/css/beesdoo.css" />
        </xpath>
    </template>
</odoo>