Updated copyright year in README

README

@@ -6,7 +6,7 @@ libisoburn and xorriso. By Vreixo Formoso <metalpain2002@yahoo.es>
 Integrated sub project of libburnia-project.org.
 http://files.libburnia-project.org/releases/libisoburn-1.5.2.tar.gz
 Copyright (C) 2006-2009 Vreixo Formoso,
-Copyright (C) 2006-2019 Thomas Schmitt.
+Copyright (C) 2006-2020 Thomas Schmitt.
 Provided under GPL version 2 or later.
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