Update README.md

Author: mitchell-elholm

ruby/cluster_management/README.md

@@ -39,9 +39,6 @@ ruby --version
 ### Execute tests to create and delete clusters
 
 ```sh
-# MacOS optional: Use rbenv to manage Ruby version
-rbenv install 3.3.5  
-
 # Optional: Single-Region examples will execute in REGION_1. Defaults to 'us-east-1'.
 export REGION_1="us-east-1"
 
@@ -73,4 +70,4 @@ REGION_1="us-east-1" CLUSTER_ID_1="<your cluster id>" \
 
 Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 
-SPDX-License-Identifier: MIT-0
+SPDX-License-Identifier: MIT-0