[hotfix] Update datetime formatter to actually produce and store per-…

…hour data

This closes #17

docker/data-generator/src/main/java/org/apache/flink/playground/datagen/model/TransactionSerializer.java

@@ -26,7 +26,7 @@
 public class TransactionSerializer implements Serializer<Transaction> {
 
   private static final DateTimeFormatter formatter =
-      DateTimeFormatter.ofPattern("yyyy-MM-dd hh:mm:ss");
+      DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
 
   @Override
   public void configure(Map<String, ?> map, boolean b) {}