curl --request GET \
  --url https://api.sprucecollective.co.uk/subscriptions/credit-summary \
  --header 'Authorization: <api-key>'

{
  "credits_allocated": 123,
  "credits_remaining": 123,
  "credits_used": 123,
  "period_end": "<string>",
  "period_start": "<string>",
  "total_raffle_entries": 123,
  "usage_history": [
    {
      "created_at": "<string>",
      "credits_used": 123,
      "entries_created": 123,
      "id": "<string>",
      "raffle_id": "<string>",
      "raffle_name": "<string>",
      "subscription_id": "<string>",
      "usage_type": "<string>"
    }
  ]
}