Use "custom parse format" dayjs plugin

Without this plugin the formatted date was shown as "Invalid date"

src/index.tsx

@@ -8,12 +8,16 @@
 
 import { StrictMode } from 'react';
 import { createRoot } from 'react-dom/client';
+import dayjs from 'dayjs';
+import customParseFormat from 'dayjs/plugin/customParseFormat';
 import { App } from '@/App';
 import '@/index.css';
 // roboto font
 import '@fontsource/roboto';
 import { defaultPromiseErrorHandler } from '@/util/defaultPromiseErrorHandler.ts';
 
+dayjs.extend(customParseFormat);
+
 if ('serviceWorker' in navigator) {
     navigator.serviceWorker.ready.then((registration) => {
         registration.unregister().catch(defaultPromiseErrorHandler('unregister service workers'));