Include 2020 year in Arm Copyright

Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Change-Id: I4d8b5c48c98658d014b6b220a1a37c389cd79778
diff --git a/job/tf-merge-watcher/update_reference_repo.sh b/job/tf-merge-watcher/update_reference_repo.sh
index 833ccf9..2393246 100755
--- a/job/tf-merge-watcher/update_reference_repo.sh
+++ b/job/tf-merge-watcher/update_reference_repo.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 #
-# Copyright (c) 2019, Arm Limited. All rights reserved.
+# Copyright (c) 2019-2020 Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #