Do not use deprecated strftime() function

Deprecated: Function strftime() is deprecated

src/Utilities/Date.php

@@ -610,7 +610,7 @@ public static function getDayOfWeekName(int $year, int $month, int $day): string
         $second = 0;
 
         $time = mktime($hour, $minute, $second, $month, $day, $year);
-        $name = strftime('%A', $time);
+        $name = \date('l', $time);
 
         $encoding = mb_detect_encoding($name);