Updating copyrights

New format: 'Copyright .year-present Open Networking Laboratory'

Change-Id: I1a9e58b355b775e75245ad875a2d7a4df3f03098
diff --git a/apps/dhcp/app/src/main/resources/app/view/dhcp/dhcp.css b/apps/dhcp/app/src/main/resources/app/view/dhcp/dhcp.css
index e0a2931..69515fd 100644
--- a/apps/dhcp/app/src/main/resources/app/view/dhcp/dhcp.css
+++ b/apps/dhcp/app/src/main/resources/app/view/dhcp/dhcp.css
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 Open Networking Laboratory
+ * Copyright 2015-present Open Networking Laboratory
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.