update changelog for v1.5.0 (#67)

Author: m-Bilal

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.5.0]
+
 - Add support for a credentials provider service ([#65](https://github.com/hasura/ndc-elasticsearch/pull/65))
 
 ## [1.4.1]