Updated comment (#526)

requirements-cli.txt

@@ -4,7 +4,7 @@ pip
 awscli
 awscurl                   # https://github.com/okigan/awscurl
 awslogs                   # https://github.com/jorgebastida/awslogs
-#aws-shell                # https://github.com/awslabs/aws-shell
+#aws-shell                # https://github.com/awslabs/aws-shell (not actively maintained)
 #aws-encryption-sdk-cli   # CLI wrapper around aws-encryption-sdk-python, https://github.com/aws/aws-encryption-sdk-cli
 #aws-parallelcluster      # https://github.com/aws/aws-parallelcluster
 #awsebcli                 # https://github.com/aws/aws-elastic-beanstalk-cli