README: link to correct relative files

Author: mmlb

README.md

@@ -101,9 +101,9 @@ https://github.com/koalalorenzo/python-digitalocean
 Copyright
 ---------
 
-Copyright (c) 2017 Packet Host. See [License](https://github.com/packethost/packet-python/LICENSE.txt) for further details.
+Copyright (c) 2017 Packet Host. See [License](LICENSE.txt) for further details.
 
 Changes
 -------
 
-See the [Changelog](https://github.com/packethost/packet-python/CHANGES.md) for further details.
+See the [Changelog](CHANGELOG.md) for further details.