[#1886] Update README with instructions to use 4-2-stable

README.md

@@ -21,7 +21,7 @@ To build the S3 Resource Plugin, you will need to have:
 ## Build Instructions
 
 ```
-$ git clone https://github.com/irods/irods_resource_plugin_s3
+$ git clone -b 4-2-stable https://github.com/irods/irods_resource_plugin_s3
 $ mkdir build
 $ cd build
 $ cmake ../irods_resource_plugin_s3