LICENSE: update copyright date

Grimler91 · Grimler91 · commit 19e7b9f6c648 · 2021-11-28T12:28:29.000+01:00
diff --git a/LICENSE b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2017 Termux
+Copyright (c) 2017-2021 Termux
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
