Update chat page with Let's Encrypt SSL details

Signed-off-by: David Goulet <dgoulet@ev0ke.net>

chat.html

@@ -70,11 +70,11 @@
 				<p class="indent">Protocol: <code>jabber</code> or <code>xmpp</code></p>
 				<p class="indent">Account: <code>username@jabber.otr.im</code></p>
 
-				<p>Our Jabber server requires a secure <a href="https://en.wikipedia.org/wiki/Transport_Layer_Security" target="_blank">SSL/TLS</a> connection. Here is the
-				SSL fingerprint you should expect:</p>
-
-				<p class="indent">SHA256:
-				<code>C9:DD:09:15:DD:25:FE:69:65:1C:2D:81:47:46:A1:99:94:73:FA:1D:31:31:09:31:FE:69:2C:87:1F:94:E2:30</code>
+				<p>Our Jabber server requires a secure <a
+					href="https://en.wikipedia.org/wiki/Transport_Layer_Security"
+					target="_blank">SSL/TLS</a> connection. We use Let's
+				Encrypt since March 22nd, 2016 thus you should expect a valid
+				signed certificate for <code>jabber.otr.im</code>.
 				</p>
 
 				<p>Finally, this server has a special quirk. It forces