Support for XML Schema 1.1 validation

Author: costas80

etc/licence/overrides.txt

@@ -2,4 +2,5 @@ org.webjars--font-awesome--5.13.0=MIT License
 eu.europa.ec.itb.xerces--cupv10k-runtime--2.12.2-xsd11=CUP Parser Generator Copyright Notice, License, and Disclaimer
 eu.europa.ec.itb.xerces--icu4j--2.12.2-xsd11=ICU License - ICU 1.8.1 and later
 eu.europa.ec.itb.xerces--org.eclipse.wst.xml.xpath2.processor_1.2.1--2.12.2-xsd11=Eclipse Public License - v1.0
-eu.europa.ec.itb.xerces--xercesImpl--2.12.2-xsd11=Apache License, Version 2.0
+eu.europa.ec.itb.xerces--xercesImpl--2.12.2-xsd11=Apache License, Version 2.0
+xalan--serializer--2.7.3=Apache License, Version 2.0