Contribute WindowBuilder RC2 for 2023-09

Change-Id: Ie0247431cf2336811e888c828e26fa7faf24fb11
diff --git a/windowbuilder.aggrcon b/windowbuilder.aggrcon
index bc47129..f7f8fd6 100644
--- a/windowbuilder.aggrcon
+++ b/windowbuilder.aggrcon
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="ASCII"?>
 <aggregator:Contribution xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:aggregator="http://www.eclipse.org/cbi/p2repo/2011/aggregator/1.1.0" description="Window Builder GUI Designer" label="Window Builder">
-  <repositories location="https://download.eclipse.org/windowbuilder/updates/milestone/S202308300408" description="WindowBuilder 1.13.0">
+  <repositories location="https://download.eclipse.org/windowbuilder/updates/milestone/S202309051601" description="WindowBuilder 1.13.0">
     <features name="org.eclipse.wb.core.feature.feature.group">
       <categories href="simrel.aggr#//@customCategories[identifier='General%20Purpose%20Tools']"/>
     </features>