Bump version to 1.18.13

debian/changelog

@@ -1,3 +1,9 @@
+dpkg (1.18.13) UNRELEASED; urgency=medium
+
+  *
+
+ -- Guillem Jover <guillem@debian.org>  Sun, 06 Nov 2016 06:28:11 +0100
+
 dpkg (1.18.12) unstable; urgency=medium
 
   * Build system: