Update copyright year from 2020 to 2021
diff --git a/include/stack_macros.h b/include/stack_macros.h
index 7b4c698..c728988 100644
--- a/include/stack_macros.h
+++ b/include/stack_macros.h
@@ -1,6 +1,6 @@
/*
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
- * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in