postfix: Add missing transport.pcre

Signed-off-by: Florian Pritz <bluewind@xinu.at>

roles/postfix/templates/transport.pcre.j2

+{% if postfix_server %}
+/wikibounce-[\w.]+-\w+-\w+-\w...............@archlinux.org/  wiki_bouncehandler:
+{% endif %}