static Dependency fromArtifact(Artifact a) {
            return new Dependency(
                    a.getGroupId(), a.getArtifactId(), a.getVersion(), Optional.ofNullable(a.getClassifier()));
        }
Only return the projects we'd like to enforce dependencies for: the root project, its modules, their modules, etc.
vespa-enforcer-extensions/src/main/java/com/yahoo/vespa/maven/plugin/enforcer/AllowedDependencies.java