This gist will produce a zip archive including the release artifacts of any subprojects

distZip.gradle

task distributionZip(type: Zip) {
    archiveName = "${project.name}.zip"

    subprojects.each { subproject ->
        inputs.dir subproject.buildDir
        into(subproject.name) {
            from subproject.buildDir
            include 'docs/**'
            include 'libs/**'
            include 'reports/**'
            include 'test-results/**'
        }
    }
}