source-release.zip contains IT results

[hboutemy]

discovered while rebuilding 1.1.0 and 1.2.0 for Reproducible Builds: https://github.com/jvm-repo-rebuild/reproducible-central/blob/master/content/org/codehaus/mojo/xml-maven-plugin/README.md

for example src/test/it4/target/generated-resources/xml/xslt/doc1.xml
see full https://github.com/jvm-repo-rebuild/reproducible-central/blob/master/content/org/codehaus/mojo/xml-maven-plugin/xml-maven-plugin-1.1.0.diffoscope