Fix CHANGELOG

Author: dimuon

CHANGELOG.md

@@ -188,7 +188,8 @@
 - Initial set of docs
 - CI integration
 
-[Unreleased]: https://github.com/elastic/terraform-provider-elasticstack/compare/v0.8.0...HEAD
+[Unreleased]: https://github.com/elastic/terraform-provider-elasticstack/compare/v0.9.0...HEAD
+[0.9.0]: https://github.com/elastic/terraform-provider-elasticstack/compare/v0.8.0...v0.9.0
 [0.8.0]: https://github.com/elastic/terraform-provider-elasticstack/compare/v0.7.0...v0.8.0
 [0.7.0]: https://github.com/elastic/terraform-provider-elasticstack/compare/v0.6.2...v0.7.0
 [0.6.2]: https://github.com/elastic/terraform-provider-elasticstack/compare/v0.6.1...v0.6.2