Update copyright year

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14801)

test/cmp_hdr_test.c

diff --git a/test/cmp_hdr_test.c b/test/cmp_hdr_test.c
index 617d780..ce0038d 100644
--- a/test/cmp_hdr_test.c
+++ b/test/cmp_hdr_test.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2007-2020 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2007-2021 The OpenSSL Project Authors. All Rights Reserved.
  * Copyright Nokia 2007-2019
  * Copyright Siemens AG 2015-2019
  *