Update footer copyright text

Signed-off-by: lucperkins <[email protected]>

layouts/partials/footer.html

@@ -3,7 +3,11 @@
 <footer class="footer has-background-dark has-text-centered">
     <img class="is-footer-logo" src="{{ $logo }}" alt="etcd footer logo">
 
+  <p class="is-size-4 is-size-5-mobile has-text-white-bis has-text-weight-light">
+    &copy; etcd Authors {{ $year }} | Documentation Distributed under CC-BY-4.0
+  </p>
+
   <p class="is-size-5 is-size-6-mobile has-text-white-bis has-text-weight-light">
-    &copy; {{ $year }} The etcd authors
+    &copy; {{ $year }} The Linux Foundation. All rights reserved. The Linux Foundation has registered trademarks and uses trademarks.<br />For a list of trademarks of The Linux Foundation, please see our Trademark Usage page.
   </p>
 </footer>