[MINOR] Update NOTICE file to reflect the correct date

Author: jerryshao <jerryshao@tencent.com>

Closes #271 from jerryshao/notice-fix.
diff --git a/NOTICE b/NOTICE
index 7eeebe8..9d023c2 100644
--- a/NOTICE
+++ b/NOTICE
@@ -1,5 +1,5 @@
 Apache Livy
-Copyright 2018 The Apache Software Foundation
+Copyright 2018 and onwards The Apache Software Foundation
 
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).