Anchor the year anchor date to local midnight

src/main/js/main.js

@@ -268,6 +268,7 @@ class DoomsdayDate {
         const anchorDate = new Date(this.date);
         anchorDate.setDate(4); // 4th
         anchorDate.setMonth(3); // April
+        anchorDate.setHours(0); // midnight local time
         return DoomsdayDate.getWeekDayOf(anchorDate);
     };