Fixed designer's pom.xml

Signed-off-by: Tilman Kamp <tilmankamp@posteo.de>

features/org.eclipse.smarthome.feature.designer/feature.xml

@@ -137,7 +137,7 @@
          unpack="false"/>
 
    <plugin
-         id="org.eclipse.smarthome.io.multimedia"
+         id="org.eclipse.smarthome.io.voice"
          download-size="0"
          install-size="0"
          version="0.0.0"