Update XSD-PROCEED.xsd with userDefinedId

add userDefinedId attribute for definitions

Author: iaktern

public/xsd/XSD-PROCEED.xsd

@@ -14,6 +14,7 @@
   <xsd:attribute name="creatorId" type="xsd:string" />
   <xsd:attribute name="creatorName" type="xsd:string" />
   <xsd:attribute name="creatorUsername" type="xsd:string" />
+  <xsd:attribute name="userDefinedId" type="xsd:string" />
   <!-- for extension in the BPMN 'definition' element for process imports -->
   <xsd:attribute name="originalId" type="xsd:ID" />
   <xsd:attribute name="originalExporter" type="xsd:string" />