Create and manage EasyPost Carrier Accounts for multiple carriers using the CarrierAccount API

Steps

1. POST to /v2/carrier_accounts with the carrier type string (e.g., UPSAccount, FedExAccount) and the required credentials object for that carrier to register the account
2. Retrieve a list of all connected carrier accounts via GET /v2/carrier_accounts to confirm registration and obtain the carrier_account id for future shipment creation
3. Update credentials for an existing carrier account (e.g., after a password rotation) by sending a PUT to /v2/carrier_accounts/{id} with the updated credentials fields
4. When creating a Shipment, pass the carrier_accounts array with the desired carrier_account id to restrict rate shopping to that specific account rather than all connected accounts
5. Delete a decommissioned carrier account via DELETE /v2/carrier_accounts/{id} to prevent it from appearing in rate results