add missing itag spec

i2p2www/pages/site/docs/transport/ssu.html

 {% extends "global/layout.html" %}
 {% block title %}{% trans %}Secure Semireliable UDP{% endtrans %} (SSU){% endblock %}
-{% block lastupdated %}{% trans %}September 2017{% endtrans %}{% endblock %}
+{% block lastupdated %}{% trans %}October 2017{% endtrans %}{% endblock %}
 {% block accuratefor %}0.9.32{% endblock %}
 {% block content %}
 
@@ -64,6 +64,10 @@ The following properties are stored in the network database.
 </li><li><b>iport[0-2]:</b> Introducer's port 1024 - 65535.
   Only present if firewalled, and introducers are required.
   <a href="#introduction">{% trans %}See below{%- endtrans %}</a>.
+</li><li><b>itag[0-2]:</b> Introducer's tag 1 - (2**32 - 1)
+  ASCII digits.
+  Only present if firewalled, and introducers are required.
+  <a href="#introduction">{% trans %}See below{%- endtrans %}</a>.
 </li><li><b>key:</b> Base 64 introduction key. <a href="#key">{% trans %}See below{%- endtrans %}</a>.
 </li><li><b>mtu:</b> Optional. Default and max is 1484. Min is 620.
   Must be present for IPv6, where the min is 1280 and the max is 1488