Azure.Security.KeyVault.Certificates 4.0.0-preview.7

- Moved Cancel and Delete certificate operation methods from CertificateClient to CertificateOperation. - CertificateClient.DeleteCertificate has been renamed to CertificateClient.StartDeleteCertificate and now returns a DeleteCertificateOperation to track this long-running operation. - CertificateClient.RecoverDeletedCertificate has been renamed to CertificateClient.StartRecoverDeletedCertificate and now returns a RecoverDeletedCertificateOperation to track this long-running operation. - CertificateIssuer.Administrators has been renamed to CertificateIssuer.AdministratorContacts. - CertificateKeyType.Oct has been removed. - The SubjectAlternativeNames class now allows you to add multiple types of subject alternative names using any of the DnsNames, Emails, and UserPrincipalNames collection properties. See https://github.com/Azure/azure-sdk-for-net/tree/Azure.Security.KeyVault.Certificates_4.0.0-preview.7/sdk/keyvault/Azure.Security.KeyVault.Certificates/ChangeLog.md for more detailed changes.