Get historical balance

curl --request GET \
  --url https://api.enterprise.sandbox.uphold.com/core/portfolio/historical-balance \
  --header 'Authorization: Bearer <token>'

{
  "historicalBalance": [
    {
      "timestamp": "2020-01-01T00:00:00Z",
      "balance": {
        "total": "1000.00",
        "available": "950.00"
      }
    },
    {
      "timestamp": "2020-01-02T00:00:00Z",
      "balance": {
        "total": "1200.00",
        "available": "1150.00"
      }
    }
  ]
}