How do I writeMaven pom packaging element with maven plugin?

How do I assure that the maven <packaging/> element shows up in a pom with the maven plugin?

When I do this:

uploadArchives {
    repositories {
        mavenDeployer {
            pom.project {
                packaging = "jar"
                description = "xxx"

I notice that the packaging element does not show up in the generated pom.