[AMQ-8578] Upgrade to xbean 4.21

Author: jbonofre

pom.xml

@@ -114,7 +114,7 @@
     <xalan-version>2.7.2</xalan-version>
     <xpp3-version>1.1.4c</xpp3-version>
     <xstream-version>1.4.19</xstream-version>
-    <xbean-version>4.20</xbean-version>
+    <xbean-version>4.21</xbean-version>
     <xerces-version>2.12.2</xerces-version>
     <jaxb-basics-version>0.12.0</jaxb-basics-version>
     <stompjms-version>1.19</stompjms-version>