List contract types

curl --request GET \
  --url https://api.buildr.com/api/2023-01/contract_types \
  --header 'Authorization: <authorization>'

{
  "contract_types": [
    {
      "id": "721",
      "created_at": "2023-02-14T18:13:00Z",
      "updated_at": "2023-04-03T20:16:30Z",
      "name": "Design/Build"
    }
  ]
}