input datetime-local needs day to also be two digits

games/static/js/utils.js

@@ -4,6 +4,14 @@
  * @returns {string}
  */
 export function toISOUTCString(date) {
-  let month = (date.getMonth() + 1).toString().padStart(2, 0);
+  function stringAndPad(number) {
-  return `${date.getFullYear()}-${month}-${date.getDate()}T${date.getHours()}:${date.getMinutes()}`;
+    return number.toString().padStart(2, 0);
+  }
+  return `${
+    date.getFullYear()}-
+    ${stringAndPad(date.getMonth() + 1)}-
+    ${stringAndPad(date.getDate())}T
+    ${stringAndPad(date.getHours())}:
+    ${stringAndPad(date.getMinutes())
+  }`;
 }