Update LICENSE year

ronaldtse · antonsviridenko · commit 94303b724568 · 2021-03-21T00:05:41.000+04:00
diff --git a/LICENSE.md b/LICENSE.md
@@ -8,7 +8,7 @@ This license file adheres to the formatting guidelines of
 Ribose's BSD 2-Clause License
 -----------------------------
 
-Copyright (c) 2017, [Ribose Inc](https://www.ribose.com).
+Copyright (c) 2017-2021, [Ribose Inc](https://www.ribose.com).
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification,
