List all availabilities

curl --request GET \
  --url https://api.caspen.com/v1/availabilities

{
  "data": [
    {
      "id": "<string>",
      "created_at": "<string>",
      "date": "<string>",
      "day": "<string>",
      "end_time": "<string>",
      "location_id": "<string>",
      "practitioner_id": "<string>",
      "repeating": true,
      "repeating_end_date": "<string>",
      "repeating_interval": "<string>",
      "start_time": "<string>"
    }
  ]
}