Bump version to 1.18.23

debian/changelog

@@ -1,3 +1,9 @@
+dpkg (1.18.23) UNRELEASED; urgency=medium
+
+  *
+
+ -- Guillem Jover <guillem@debian.org>  Wed, 01 Feb 2017 06:28:28 +0100
+
 dpkg (1.18.22) unstable; urgency=medium
 
   [ Guillem Jover ]