fix: message.max.bytes should default to 1048576 (#2804)

Sarama should match the max.request.size default from the Java producer config.

https://kafka.apache.org/documentation/#producerconfigs_max.request.size

Note that the server has its own limit on the record batch size which
defaults to slightly higher than this, but is configurable and can also
be set per topic too.

https://kafka.apache.org/documentation/#brokerconfigs_message.max.bytes

Co-authored-by: Cassondra Foesch <[email protected]>

Signed-off-by: Dominic Evans <[email protected]>

config.go

@@ -523,7 +523,7 @@ func NewConfig() *Config {
 	c.Metadata.Full = true
 	c.Metadata.AllowAutoTopicCreation = true
 
-	c.Producer.MaxMessageBytes = 1000000
+	c.Producer.MaxMessageBytes = 1024 * 1024
 	c.Producer.RequiredAcks = WaitForLocal
 	c.Producer.Timeout = 10 * time.Second
 	c.Producer.Partitioner = NewHashPartitioner