kamailio.cfg: updated wiki link to match the version

etc/kamailio.cfg

@@ -6,7 +6,7 @@
 #
 # Direct your questions about this file to: <[email protected]>
 #
-# Refer to the Core CookBook at http://www.kamailio.org/dokuwiki/doku.php
+# Refer to the Core CookBook at http://www.kamailio.org/wiki/
 # for an explanation of possible statements, functions and parameters.
 #
 # Several features can be enabled using '#!define WITH_FEATURE' directives: