I am trying to use Jenkins to publish npm packages to a private npm repository.  I use the config-file-provider plugin to create a new npm config file.

Creating the config looks like this:

The credentials used in that config is a "username with password" credentials configured with the correct username/password for publishing to my repository.

The publish part of my Jenkinsfile looks like:

nodejs(nodeJSInstallationName: "6.12.0", configId: "npm-publish-config") {
    lerna publish --conventional-commits --yes
}

When I run the build I get the following error when it tries to publish: 

need auth You need to authorize this machine using `npm adduser`

I did a little debugging.  I was able to find the file it claims to have used as it's npm config:

@myScope:registry = http://my.private.registry/
 //my.private.registry/:always-auth = true
 //my.private.registry/:username = jenkins
 //my.private.registry/:_password = <<redacted>>

I have found no information online about the :username and :_password properties being supported by NPM.  Everything I have found has said that the .npmrc config file should have an _authToken property like this:

@myScope:registry = http://my.private.registry/
 //my.private.registry/:always-auth = true
 //my.private.registry/:_authToken="SECRET"

What am I doing wrong?