chore: update credits

Author: orisano

CREDITS

@@ -36,7 +36,7 @@ https://github.com/orisano/usage
 ----------------------------------------------------------------
 MIT License
 
-Copyright (c) 2018 Nao YONASHIRO
+Copyright (c) 2019-2020 Nao Yonashiro
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal