Add tag of ada-zangemann (#5978)

Reviewed-on: #5978

fsfe.org/events/2025/event-20250327-01.en.xml

@@ -25,6 +25,7 @@
             <tag key="talk"/>
 <tag key="panel"/>
 <tag key="localgroup"/>
+        <tag key="ada-zangemann"/>
       <tag key="front-page"/>
     </tags>
   </event>