Use latest Xerces 2.12 release

[rjmartell]

At long last Xerces 2.12 has been released. It provides a fully compliant XML Schema 1.1 implementation. This can replace the shaded pre-release build that is currently being used.

[keshavnangare]

I have updated the Xerces 2.12.0 dependency and the ValidationUtils class get broken from ets-kml2.
Failed with following lines:

ets-kml2/src/main/java/org/opengis/cite/kml2/util/ValidationUtils.java

Lines 186 to 187 in 23515a1

	Constants.W3C_XML_SCHEMA11_NS_URI,
	"org.opengis.cite.xerces.jaxp.validation.XMLSchema11Factory",

Currently kml2 is using the XML Schema 1.1 but the new release of Xerces 2.12.0 don't have the XML schema 1.1 constant and XMLSchema11Factory class which is used by the ets-kml2, so we cannnot use this version directly. I got the another tag with Xerces-j_2_12_0-xml-schema-1.1 which is having both constant and XMLSchema11Factory class. But this tag did not released with maven central repository.

Here you can see differences between tags:

Without xml schema 1.1
https://github.com/apache/xerces2-j/blob/Xerces-J_2_12_0/src/org/apache/xerces/impl/Constants.java#L41

Class XMLSchema11Factory is not present:
https://github.com/apache/xerces2-j/tree/Xerces-J_2_12_0/src/org/apache/xerces/jaxp/validation

With XML schema 1.1
Constant can be found here:

https://github.com/apache/xerces2-j/blob/d173aa11e99ca613ddd714205f1dfd62f4b62ab1/src/org/apache/xerces/impl/Constants.java#L41-L44

Class XMLShecma11Factory can be found here: https://github.com/apache/xerces2-j/tree/Xerces-J_2_12_0-xml-schema-1.1/src/org/apache/xerces/jaxp/validation

Release related reference: http://apache-xml-project.6118.n7.nabble.com/Xerces2-Java-2-12-0-XML-Schema-1-1-in-maven-repository-td44927.html#a44945

[aprojectfinal]

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