doc: update copyright year
Signed-off-by: Daiki Ueno <ueno@gnu.org>
diff --git a/doc/libtasn1.texi b/doc/libtasn1.texi
index b57e74d..2879d28 100644
--- a/doc/libtasn1.texi
+++ b/doc/libtasn1.texi
@@ -15,7 +15,7 @@
which is a library for Abstract Syntax Notation One (ASN.1) and
Distinguished Encoding Rules (DER) manipulation.
-Copyright @copyright{} 2001-2020 Free Software Foundation, Inc.
+Copyright @copyright{} 2001-2021 Free Software Foundation, Inc.
@quotation
Permission is granted to copy, distribute and/or modify this document
