Add David Brownell as zcip maintainer.

diff --git a/AUTHORS b/AUTHORS
index 3673861..ebf57b6 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -29,6 +29,9 @@
 John Beppu <beppu@codepoet.org>
     du, nslookup, sort
 
+David Brownell <dbrownell@users.sourceforge.net>
+    zcip
+
 Brian Candler <B.Candler@pobox.com>
     tiny-ls(ls)