curl --request GET \
  --url http://localhost:3001/v1/invoice/{id}/approval-request \
  --header 'Authorization: Bearer <token>'

{
  "id": "<string>",
  "status": "PENDING",
  "requestedAt": "2023-11-07T05:31:56Z",
  "requester": {
    "id": "<string>",
    "name": "<string>",
    "email": "<string>"
  },
  "approvalItems": [
    {
      "id": "<string>",
      "approver": {
        "id": "<string>",
        "name": "<string>",
        "email": "<string>"
      },
      "status": "PENDING",
      "comments": "<string>",
      "decidedAt": "2023-11-07T05:31:56Z",
      "step": {
        "stepNumber": 123
      }
    }
  ]
}