.update-copyright.conf: Automate maintenance for AUTHORS

Use my external update-copyright package [1] to maintain the AUTHORS
file.  Don't maintain the copyright blurbs though, since this project
sticks to:

  Copyright (c) 2014 Docker.
  <Apache blurb>

and doesn't list the file's individual contributors.

[1]: http://pypi.python.org/pypi/update-copyright/

Author: wking

.update-copyright.conf

@@ -0,0 +1,7 @@
+[project]
+name: docker-registry
+vcs: Git
+
+[files]
+authors: yes
+files: no