Verdaccio: How to add custom generated auth plugin in config.yml of local registry

Question

I created a custom authentication plugin in verdaccio but I am unable to add it to my local registry config.yml. I tried adding it using the following code:

middlewares:
  custom-auth:
    enabled: true

auth:
  custom-auth:
    option: foo

However, I am getting a "package not found" error.