Cannot create extra configs using Helm deployment

I am deploying Nextcloud using the official Helm chart. The deployment is functioning well overall. However, I am unable to create a custom config file using the Chart. There is a section in the Helm Chart values that I want to look like what is shown below so that Traefik will be set as one of the trusted_proxies. When I open a terminal session to the running Nextcloud container, I see that the config my.config.php is never created.

    # To protect /var/www/html/config
    .htaccess: true
    # Redis default configuration
    redis.config.php: true
    # Apache configuration for rewrite urls
    apache-pretty-urls.config.php: true
    # Define APCu as local cache
    apcu.config.php: true
    # Apps directory configs
    apps.config.php: true
    # Used for auto configure database
    autoconfig.php: true
    # SMTP default configuration
    smtp.config.php: true
    # My custom config
    my.config.php: true

    my.config.php: |-
      $CONFIG = array (
        'trusted_proxies'   => ['traefik'],