Update all 2011 dates to 2021.
diff --git a/cmake/make_cmakelists.py b/cmake/make_cmakelists.py
index c639864..c58e134 100755
--- a/cmake/make_cmakelists.py
+++ b/cmake/make_cmakelists.py
@@ -1,6 +1,6 @@
 #!/usr/bin/python
 #
-# Copyright (c) 2009-2011, Google LLC
+# Copyright (c) 2009-2021, Google LLC
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without