How can I specify the authentication credentials for the Confluent Schema Registry client when using the Schema Registry with Protobuf functions in Databricks?
You can specify the authentication credentials for the Confluent Schema Registry client using the `confluent.schema.registry.<schema-registy-client-option>` option. For example, to provide "USER_INFO" authentication credentials, you can set the following two options:

* `confluent.schema.registry.basic.auth.credentials.source`: 'USER_INFO'
* `confluent.schema.registry.basic.auth.user.info`: "<KEY>:<SECRET>"

Replace `<KEY>` and `<SECRET>` with your actual authentication key and secret.