This release adds Private App (Oauth) support to the library, see #92 and #93 / #96
The library still supports private key auth, so it should be non breaking, however keep in mind that HubSpot will end support for api key auth on nov 30'th.
See more here:
https://developers.hubspot.com/docs/api/migrate-an-api-key-integration-to-a-private-app