Doc: Update license years

sttk · sttk · commit 72270af97f86 · 2020-09-21T17:00:52.000+09:00
diff --git a/LICENSE b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2016 Takayuki Sato
+Copyright (c) 2016-2020 Takayuki Sato
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
@@ -209,7 +209,7 @@ If *converter* is given, it is able to convert the terminal values.
 
 ## License
 
-Copyright (C) 2016-2018 Takayuki Sato
+Copyright (C) 2016-2020 Takayuki Sato
 
 This program is free software under [MIT][mit-url] License.
 See the file LICENSE in this distribution for more details.
