Update changelog

CHANGELOG.md

@@ -4,6 +4,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [0.9.0] - 2020-07-07
+## [0.9.1] - 2020-07-13
+### Added
+- More specific warning and error messages for common configuration issues ([PR12](https://github.com/observIQ/carbon/pull/12),[PR13](https://github.com/observIQ/carbon/pull/13),[PR14](https://github.com/observIQ/carbon/pull/14))
+### Fixed
+- Writing from files being actively written to will sometimes read partial entries ([PR21](https://github.com/observIQ/carbon/pull/21))
+- Minor documentation omissions
 
-Initial Open Source Release
+## [0.9.0] - 2020-07-07
+### Added
+- Initial open source release. See documentation for full list of supported features in this version.