Add dash to make meaning clearer

Author: leerho

NOTICE

@@ -3,7 +3,7 @@ Copyright 2025 The Apache Software Foundation
 
 Copyright 2015-2018 Yahoo Inc.
 Copyright 2019-2020 Verizon Media
-Copyright 2021 Yahoo Inc.
+Copyright 2021-     Yahoo Inc.
 
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).