switch default value in doc

Author: julian

README.md

@@ -88,7 +88,7 @@ The rest of the settings in `defaults/main.yml` control MySQL's memory usage. Th
 
     mysql_server_id: "1"
     mysql_max_binlog_size: "100M"
-    mysql_binlog_format: "STATEMENT"
+    mysql_binlog_format: "ROW"
     mysql_expire_logs_days: "10"
     mysql_replication_role: ''
     mysql_replication_master: ''