document: update copyright

MeilCli · MeilCli · commit d8dcfaf9472c · 2021-02-23T16:33:08.000+09:00
diff --git a/LICENSE b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2019 meil
+Copyright (c) 2019-2021 meil
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
