Retrieve a sales milestone by ID

curl --request GET \
  --url https://api.zivio.net/api/v3/sales_milestones/{id} \
  --header 'X-API-Key: <api-key>' \
  --header 'zivio-tenant-id: <api-key>'

{
  "id": "66",
  "client_suggested": "true",
  "title": "Title of Milestone",
  "details": "Details of Milestone",
  "rate": "1500.00",
  "ccy": "GBP",
  "due_on": "2023-11-07T05:31:56Z",
  "notes": "some notes relating to the milestone",
  "comments": "some comments relating to the milestone",
  "job_id": "2669",
  "job_summary": "summary of miestone",
  "created_at": "2023-11-07T05:31:56Z",
  "updated_at": "2023-11-07T05:31:56Z",
  "status": "open",
  "approved_at": "2023-11-07T05:31:56Z",
  "approved_by": {
    "id": "7158",
    "first_name": "Jack",
    "last_name": "Jones",
    "email": "jack_jones@example.com",
    "org_name": "Organisation Ltd",
    "org_id": "567",
    "business_unit": "Public Private Partnerships",
    "division": "Infastructure",
    "department": "Bridges",
    "vetting_status": "PASSED",
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z",
    "custom_fields": {
      "key": "value"
    },
    "has_oversight": "<string>"
  },
  "children": [
    "124"
  ],
  "parents": [
    "14"
  ],
  "custom_fields": {
    "key": "value"
  }
}