Quite late to respond but based on the document, you need to add the bearer token [using the http_config][1]

- job_name: 'test'
  metrics_path: "/metrics"
  scheme: "http"
  authorization: 
    type: Bearer 
    credentials: <your-secret>
    credentials_file: <file-location-of-your-secret>
  static_configs:
    - targets: ['host.com']

Either credentials or credentials_file should be provided. [1]: https://prometheus.io/docs/prometheus/latest/configuration/configuration/#http_config