update adsf lib version to rc2 in the example (#205)

Author: vgkowski

examples/spark-data-lake/README.md

@@ -49,7 +49,7 @@ git init
 ```
 aws-cdk-lib==2.94.0
 constructs>=10.2.55, <11.0.0
-aws_dsf==1.0.0-rc1
+aws_dsf==1.0.0-rc2
 ```
 
 2. From the `./infra` folder, create Python3 virtual environment and activate it: