Contributing UML2 5.5.2 M1 for SimRel 2021-03 M1 build.

Signed-off-by: Kenn Hussey <kenn.hussey@gmail.com>
diff --git a/mdt-uml2.aggrcon b/mdt-uml2.aggrcon
index 1d3e5eb..3aa8d7b 100644
--- a/mdt-uml2.aggrcon
+++ b/mdt-uml2.aggrcon
@@ -1,10 +1,10 @@
 <?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" label="MDT UML2">
-  <repositories location="https://download.eclipse.org/modeling/mdt/uml2/updates/5.5" description="UML2 5.5 Releases">
-    <features name="org.eclipse.uml2.sdk.feature.group" versionRange="[5.5.1.v20200302-1312]">
+  <repositories location="https://download.eclipse.org/modeling/mdt/uml2/updates/5.5milestones" description="UML2 5.5 Milestones">
+    <features name="org.eclipse.uml2.sdk.feature.group" versionRange="[5.5.2.v20210110-1527]">
       <categories href="simrel.aggr#//@customCategories[identifier='Modeling']"/>
     </features>
-    <features name="org.eclipse.uml2.sdk.source.feature.group" versionRange="[5.5.1.v20200302-1312]">
+    <features name="org.eclipse.uml2.sdk.source.feature.group" versionRange="[5.5.2.v20210110-1527]">
       <categories href="simrel.aggr#//@customCategories[identifier='Modeling']"/>
     </features>
   </repositories>