Log Message:
py-braintree: updated to 3.50.0

3.50.0
Add fraud_service_provider field to risk_data
Add authorization_expires_at to Transaction
Remove invalid transaction tests
Allow PayPal payment ID and payer ID to be passed during transaction create
Add travel_flight support to industry-specific data
Add processor_response_type to Transaction, AuthorizationAdjustment, and \ 
CreditCardVerification.