Provisioner "ansible-local" refuses to upload .yml file

I have a Packer .hcl file with an ansible-local provisioner as shown below. Packer fails to upload the .yml file. I’ve tried both with and without the packer_dir entry. With the packer_dir the error is

Error uploading playbook_dir directory: Process exited with status 255

Here is the provisioner:

provisioner “ansible-local” {
playbook_dir = “./ansible”
playbook_file = “./ansible/playbookdemo.yml”

Does ansible-local provisioner actually work in HCL, or should I switch to json?