Bump version to 1.18.3

debian/changelog

@@ -1,3 +1,9 @@
+dpkg (1.18.3) UNRELEASED; urgency=low
+
+  *
+
+ -- Guillem Jover <guillem@debian.org>  Wed, 05 Aug 2015 03:10:02 +0200
+
 dpkg (1.18.2) unstable; urgency=low
 
   [ Guillem Jover ]