update to latest documentation and update copyright year
diff --git a/coders/ps2.c b/coders/ps2.c
index 242481a..16c10ca 100644
--- a/coders/ps2.c
+++ b/coders/ps2.c
@@ -17,7 +17,7 @@
 %                                 July 1992                                   %
 %                                                                             %
 %                                                                             %
-%  Copyright 1999-2020 ImageMagick Studio LLC, a non-profit organization      %
+%  Copyright 1999-2021 ImageMagick Studio LLC, a non-profit organization      %
 %  dedicated to making software imaging solutions freely available.           %
 %                                                                             %
 %  You may not use this file except in compliance with the License.  You may  %