Change license from ONF-Member-Only to Apache-2.0

Change-Id: If5c78f555fb737a18a3ae4c216ea3e2630b101bc
diff --git a/index.rst b/index.rst
index 7024d10..3c3ce81 100644
--- a/index.rst
+++ b/index.rst
@@ -1,3 +1,6 @@
+.. SPDX-FileCopyrightText: 2021 Open Networking Foundation <info@opennetworking.org>
+.. SPDX-License-Identifier: Apache-2.0
+
 .. image:: images/overview-logo.png
    :width: 400px
    :align: center