Add changelog for RFC6750 bearer token support

Not utterly convinced I like treating it like a soft token; I wonder if
it should have a dedicated callback to the UI, or be handled through
the webview support that we're working on. But there's a release imminent
and this gets people something functional.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

www/changelog.xml

@@ -25,6 +25,7 @@
        <li>Ignore missing Cisco CSD stub and simply CSD subprocess invocation (<a href="https://gitlab.com/openconnect/openconnect/merge_requests/77">!77</a>, <a href="https://gitlab.com/openconnect/openconnect/merge_requests/74">!74</a>).</li>
        <li>Pass <tt>IDLE_TIMEOUT</tt> to vpnc-script (<a href="https://gitlab.com/openconnect/openconnect/merge_requests/67">!67</a>).</li>
        <li>Windows line-ending flexibility for standard input (<a href="https://gitlab.com/openconnect/openconnect/merge_requests/78">!78</a>).</li>
+       <li>Add RFC6750 Bearer token support (<a href="https://gitlab.com/openconnect/openconnect/-/merge_requests/70">!70</a>).</li>
      </ul><br/>
   </li>
   <li><b><a href="ftp://ftp.infradead.org/pub/openconnect/openconnect-8.05.tar.gz">OpenConnect v8.05</a></b>