Change the copyright from GPL-3 to Apache-2.0

Signed-off-by: Adam Israel <adam.israel@canonical.com>

layers/vyos-proxy/copyright

@@ -2,8 +2,8 @@ Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0
 
 Files: *
 Copyright: 2015, Canonical Ltd.
-License: GPL-3
+License: Apache-2.0 
 
-License: GPL-3
+License: Apache-2.0
  On Debian GNU/Linux system you can find the complete text of the
- GPL-3 license in '/usr/share/common-licenses/GPL-3'
+ Apache-2.0 license in '/usr/share/common-licenses/Apache-2.0'