Add deprecation warning for AvroProducer and AvroConsumer in README#2159

Pradeep Kalluri (kalluripradeep) wants to merge 1 commit intoconfluentinc:masterconfluentinc/confluent-kafka-python:masterfrom

kalluripradeep:update-avro-legacy-docskalluripradeep/confluent-kafka-python:update-avro-legacy-docsCopy head branch name to clipboard