Update referral request struct

Add partner overrides to referral request (#124)

* Add partner overrides to referral request

Add this object:
https://developer.paypal.com/docs/api/partner-referrals/v2/#definition-partner_configuration_override

* Update types.go

Partner Referral API Types

Add types to support Partner Referral API (#123)

* Add types to support Partner Referral API

Add in the type structs to allow a POST call to v2/customer/partner-referrals
It sends a ReferralRequest, and returns a response of type Resource with only Links populated
https://developer.paypal.com/docs/api/partner-referrals/v2/

* Pointer for optional field

* Update types.go

Co-Authored-By: Roopak Venkatakrishnan <[email protected]>

Webhook types

Add Webhook data types (#120)

* Add Webhook data types

Add the Event data types for payment capture and merchant onboarding events, which are sent for PayPal Commerce Platform integrations.

* remove unnecessary empty line

* name change and points for omitempty objects

* Update types.go

Co-Authored-By: Roopak Venkatakrishnan <[email protected]>

Fix authorizations API

Fix authorizations (#119)

Fix authorizations

Improve webhook verification

v3.0.4

Reset after reading (#118)

Support webhook verification

v3.0.3

Add verify webhook signature response (#117)

Fix capture payment API

Merge pull request #115 from plutov/roopakv/fix_auth_capture

Fix payment capture API

Fix indirect dependency on v2

the v3 major release had an indirect dependency on v2+. This release fixes that