update readme

Author: ZhouFang928

samples/features/r-services/Retail Precision Marketing/Data/README.md

@@ -1,4 +1,5 @@
-**List of data sets**
+**List of data sets** 
+
 |  Data Set Name | Link to the Full Data Set   | Full Data Set Size (MB)  | Link to Report |
 | ---:| ---: | ---: | ---: |
 | CDNOW_master.csv | [link](https://github.com/ZhouFang928/sql-server-samples/blob/master/samples/features/r-services/Retail%20Precision%20Marketing/Data/CDNOW_master.csv) | 1.55MB | N/A|