Set correct Debian version after after 3.4.1.18 merge

debian/changelog

@@ -1,4 +1,4 @@
-emby-server (3.4.1.4-unlocked) unstable; urgency=medium
+emby-server (3.4.1.18-unlocked) unstable; urgency=medium
 
   * New upstream minor release with merged fix for premium