Setting repository credentials with -P not working

Hi, I'm trying to publish my charts to chartmuseum with the helmPublish command. I have set up my build.gradle like below, but can't get it to read the properties form command line like this: ./gradlew helmPublish -Pchartmuseum_username=myuser -Pchartmuseum_password=mypass

helm {
    ...
    publishing {
        repositories {
            chartMuseum('mycharts') {
                url = uri('// removed')
                credentials {
                    username = findProperty('chartmuseum_username')
                    password = "findProperty('chartmuseum_password')
                }
            }
        }
    }
}

I have also tried a variety of other methods like "${chartmuseum_username}", getProeprty('chartmuseum_username'), System.property('chartmuseum_username') and so on. None have worked for me.

If I insert my username and password directly in the build.gradle file, it works fine. It also works fine if I define chartmuseum_username and chartmuseum_password in my global gradle.properties file.

Any idea what's going on? I'm using the exact same approach for publishing maven artifacts, and that works fine.

unbroken-dome / gradle-helm-plugin

Setting repository credentials with -P not working #179