Maven 4 warning on iterator.remove() usage

[hazendaz]

Maven 3.9.11 started showing up with this warning.

[INFO] --- gplus:4.2.1:removeTestStubs (compileGroovy) @ spotbugs-maven-plugin ---
[WARNING] Direct modification of testCompileSourceRoots through iterator.remove() is deprecated and will not work in Maven 4.0.0. Please use the add/remove methods instead. If you're using a plugin that causes this warning, please upgrade to the latest version and report an issue if the warning persists. To disable these warnings, set -Dmaven.project.sourceRoots.warningsDisabled=true on the command line, in the .mvn/maven.config file, or in project POM properties.