#625 Update to Checkout API v68 and included sessions endpoint
Supported API versions:
Checkout API version: v68
Payments API version: v52
Recurring API version: v49
Payouts API version: v51
Account API version: v6
Fund API version: v6
Notification Configuration API version: v6
HOP API version: v6
BinLookup API version: v50
Stored Value API version: v46
POS Terminal Management version: v1
Data Protection Version: v1