Update copyright year

include/civetweb.h

@@ -1,4 +1,4 @@
-/* Copyright (c) 2013-2021 the Civetweb developers
+/* Copyright (c) 2013-2024 the Civetweb developers
  * Copyright (c) 2004-2013 Sergey Lyubka
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy

src/civetweb.c

@@ -1,4 +1,4 @@
-/* Copyright (c) 2013-2023 the Civetweb developers
+/* Copyright (c) 2013-2024 the Civetweb developers
  * Copyright (c) 2004-2013 Sergey Lyubka
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy