curl --request GET \
  --url http://localhost:8000/api/v1/subscriptions/customers/{customer_id} \
  --header 'Authorization: Bearer <token>'

[
  {
    "google_ads_customer_id": 123,
    "subscription_plan_id": 123,
    "starts_at": "2023-11-07T05:31:56Z",
    "expires_at": "2023-11-07T05:31:56Z",
    "id": 123,
    "date_added": "2023-11-07T05:31:56Z",
    "date_updated": "2023-11-07T05:31:56Z",
    "subscription_plan": {
      "name": "<string>",
      "price": "<string>",
      "id": 123,
      "date_added": "2023-11-07T05:31:56Z",
      "date_updated": "2023-11-07T05:31:56Z",
      "image_url": "<string>",
      "modules": [
        {
          "constraint": 123,
          "analysis_frequency_hours": 123,
          "id": 123,
          "date_added": "2023-11-07T05:31:56Z",
          "date_updated": "2023-11-07T05:31:56Z",
          "is_autopilot_enabled": false
        }
      ]
    },
    "cancelled_at": "2023-11-07T05:31:56Z"
  }
]