Fix typo in release version

Author: pfifer

README.md

@@ -138,7 +138,7 @@ all languages.
 
 ## Release Notes
 
-### Release 1.5.9 (February 7, 2018)
+### Release 1.5.0 (February 7, 2018)
 * Updated to version 1.9.0 of the Amazon Kinesis Client Library for Java
   * Version 1.9.0 now uses the [`ListShards` Kinesis API](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_ListShards.html), which provides a higher call rate than `DescribeStream`.
   * __WARNING: `ListShards` is a new API, and may require updating any explicit IAM policies__