Update link to upstream Kafka docs
Update link to upstream Kafka docs

the new consumer is now the standard consumer, so they dropped the `new_` from the anchor
ohmu/kafka-python,Aloomaio/kafka-python,dpkp/kafka-python,mumrah/kafka-python,ohmu/kafka-python,Aloomaio/kafka-python,dpkp/kafka-python,mumrah/kafka-python,DataDog/kafka-python,wikimedia/operations-debs-python-kafka,scrapinghub/kafka-python,scrapinghub/kafka-python,wikimedia/operations-debs-python-kafka