Unable to update to Xalan 2.7.3 due to custom functions breaking

[jodygarnett]

When attempting to sync dependencies with GeoToolsl 3.4.0 and bill of materials pom.xml CustomXPath fails.

Look at release notes for changes to functions:

• 2.7.3: https://xalan.apache.org/xalan-j/
• 2.7.2: https://xalan.apache.org/xalan-j/
• 2.7.1: https://xml.apache.org/xalan-j/readme.html