IVGCVSW-7024 Add missing license info for reuse lint

Signed-off-by: Jim Flynn <jim.flynn@arm.com>
Change-Id: I97dee6982e0a7be01c13e9e803c0997547a39ff1
diff --git a/python/pyarmnn/examples/keyword_spotting/requirements.txt b/python/pyarmnn/examples/keyword_spotting/requirements.txt
index 96782ea..9d88f90 100644
--- a/python/pyarmnn/examples/keyword_spotting/requirements.txt
+++ b/python/pyarmnn/examples/keyword_spotting/requirements.txt
@@ -1,3 +1,7 @@
+#
+# Copyright © 2021 Arm Ltd and Contributors. All rights reserved.
+# SPDX-License-Identifier: MIT
+#
 numpy>=1.19.2
 soundfile>=0.10.3
 pytest==6.2.4