List all discount codes

curl --request GET \
  --url https://api.givebutter.com/v1/campaigns/{campaign}/discount-codes \
  --header 'Authorization: Bearer <token>'

{
  "data": [
    {
      "id": "<string>",
      "campaign_id": "<string>",
      "code": "<string>",
      "type": "<string>",
      "amount": 123,
      "used": "<string>",
      "uses": "<string>",
      "active": "<string>",
      "total_discount": "<string>",
      "starts_at": "<string>",
      "expires_at": "<string>",
      "created_at": "<string>",
      "updated_at": "<string>",
      "items": "<string>",
      "all_items": "<string>"
    }
  ],
  "links": {
    "first": "<string>",
    "last": "<string>",
    "prev": "<string>",
    "next": "<string>"
  },
  "meta": {
    "current_page": 2,
    "from": 2,
    "last_page": 2,
    "links": [
      {
        "url": "<string>",
        "label": "<string>",
        "active": true
      }
    ],
    "path": "<string>",
    "per_page": 1,
    "to": 2,
    "total": 1
  }
}