Fix getting last message time

`try` is from ActiveSupport which is a development dependency.
Use a simple nil check instead.

Author: Maxim Krizhanovski

lib/kafka/consumer.rb

@@ -316,7 +316,7 @@ def each_batch(min_bytes: 1, max_bytes: 10485760, max_wait_time: 1, automaticall
               topic: batch.topic,
               partition: batch.partition,
               last_offset: batch.last_offset,
-              last_create_time: batch.messages.last.try(:create_time),
+              last_create_time: batch.messages.last && batch.messages.last.create_time,
               offset_lag: batch.offset_lag,
               highwater_mark_offset: batch.highwater_mark_offset,
               message_count: batch.messages.count,