AWS Elastic Beanstalk Mailhog deploy: Error reading auth-file: open /app/bin/auth.txt: no such file or directory

Question

The trouble is that I have an issue when I am trying to deploy the Mailhog and run it with the auth file via AWS EB in the Docker platform. The issue is:

[HTTP] Error reading auth-file: open /app/bin/auth.txt: no such file or directory. Check snapshot logs for details. (ElasticBeanstalk::ExternalInvocationError)
caused by: dcedd77ced7be4bab370671cfe92488db824bd705302ee903ca9aac50232a577

The zip file that I am packaging contains two files: auth.txt Dockerrun.aws.json

Below you can find the Dockerrun.aws.json content:

{
  "AWSEBDockerrunVersion": "1",
  "Image": {
    "Name": "mailhog/mailhog",
    "Update": "true"
  },
  "Ports": [
    {
      "HostPort": 1025,
      "ContainerPort": 1025
    },
    {
      "HostPort": 80,
      "ContainerPort": 8025
    }
  ],
  "Volumes": [
    {
      "HostDirectory": "/var/app/mailhog",
      "ContainerDirectory": "/var/app/mailhog"
    }
  ],
  "Entrypoint": "MailHog",
  "Command": "-auth-file=/var/app/auth.txt"
}

So the question is how can I specify the path to my auth file that is stored in a ZIP package?