Go SDK for CloudEvents's use of WithRoundTripper to create a Client leaks credentials

Go SDK for CloudEvents is the official CloudEvents SDK to integrate applications with CloudEvents. Prior to version 2.15.2, using cloudevents.WithRoundTripper to create a cloudevents.Client with an authenticated http.RoundTripper causes the go-sdk to leak credentials to arbitrary endpoints. When the transport is populated with an authenticated transport, then http.DefaultClient is modified with the authenticated transport and will start to send Authorization tokens to any endpoint it is used to contact. Version 2.15.2 patches this issue.