How to translate the datepicker in shipping step?

I want to add German translations to the datepicker in the shipping step of the checkout, however I cant figure out how to do it.

I found

German initialisation for the jQuery UI date picker plugin.

( function( factory ) {
    "use strict";

    if ( typeof define === "function" && define.amd ) {

        // AMD. Register as an anonymous module.
        define( [ "../widgets/datepicker" ], factory );
    } else {

        // Browser globals
        factory( jQuery.datepicker );
    }
} )( function( datepicker ) {
"use strict";

datepicker.regional.de = {
    closeText: "Schließen",
    prevText: "&#x3C;Zurück",
    nextText: "Vor&#x3E;",
    currentText: "Heute",
    monthNames: [ "Januar", "Februar", "März", "April", "Mai", "Juni",
    "Juli", "August", "September", "Oktober", "November", "Dezember" ],
    monthNamesShort: [ "Jan", "Feb", "Mär", "Apr", "Mai", "Jun",
    "Jul", "Aug", "Sep", "Okt", "Nov", "Dez" ],
    dayNames: [ "Sonntag", "Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag" ],
    dayNamesShort: [ "So", "Mo", "Di", "Mi", "Do", "Fr", "Sa" ],
    dayNamesMin: [ "So", "Mo", "Di", "Mi", "Do", "Fr", "Sa" ],
    weekHeader: "KW",
    dateFormat: "dd.mm.yy",
    firstDay: 1,
    isRTL: false,
    showMonthAfterYear: false,
    yearSuffix: "" };
datepicker.setDefaults( datepicker.regional.de );

return datepicker.regional.de;

} );

but I dont know where to initialise this; this doesnt work by default on the German storeview