Include 2020 year in Arm Copyright

Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Change-Id: I4d8b5c48c98658d014b6b220a1a37c389cd79778
diff --git a/script/gen_test_report.css b/script/gen_test_report.css
index e7d6df3..9a11600 100644
--- a/script/gen_test_report.css
+++ b/script/gen_test_report.css
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2019-2020 Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */