Updated copyright year in LICENSE

Author: zvonimir

LICENSE

@@ -1,8 +1,8 @@
 The MIT License
 
-Copyright (c) 2008-2020 Zvonimir Rakamaric (zvonimir@cs.utah.edu),
+Copyright (c) 2008-2021 Zvonimir Rakamaric (zvonimir@cs.utah.edu),
                         Michael Emmi (michael.emmi@gmail.com)
-Modified work Copyright (c) 2013-2020 Marek Baranowski,
+Modified work Copyright (c) 2013-2021 Marek Baranowski,
                                       Montgomery Carter,
                                       Pantazis Deligiannis,
                                       Jack J. Garzella,