Update Readme to change copyright year(s') (#13)

Author: arijitdas123student

README.adoc

@@ -13,7 +13,7 @@ This library is based on https://www.kernel.org[Linux Kernel's] V4L2 driver for
 
 == License ==
 
-Copyright (c) 2020 Arduino SA. All rights reserved.
+Copyright (c) 2021 Arduino SA. All rights reserved.
 
 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2.