Add link to legacy Datagen in deployed site

Author: szarnyasg

dist/README.md

@@ -6,7 +6,7 @@ This README is deployed to <http://ldbcouncil.org/ldbc_snb_datagen_spark>.
 
 The following data sets are generated for the `dev` variant, to be used for the BI workload.
 
-If you are looking for data sets to implement the Interactive workload, please consult the `stable` branch or reach out to us.
+If you are looking for data sets to implement the Interactive workload, please use the [Hadoop-based legacy  Datagen](https://github.com/ldbc/ldbc_snb_datagen_hadoop) or reach out to us.
 
 {% for file in site.static_files %}
   {% if file.extname == ".zip" -%}