update end year in NOTICE
diff --git a/NOTICE b/NOTICE
index 41afaf5..6f3c523 100644
--- a/NOTICE
+++ b/NOTICE
@@ -1,5 +1,5 @@
 Apache Dubbo Go Hessian2
-Copyright 2018-2019 The Apache Software Foundation
+Copyright 2018-2020 The Apache Software Foundation
 
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).