update CHANGELOG for version 0.9.0

Author: joshuadavidthomas

CHANGELOG.md

@@ -18,6 +18,8 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 
 ## [Unreleased]
 
+## [0.9.0]
+
 ### Changed
 
 - Changed `installation_repositories` internal event handlers to automatically create missing `Installation` models using new `(a)get_or_create_from_event` method, eliminating the need for manual import when connecting to pre-existing GitHub App installations.
@@ -123,7 +125,7 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 
 - Josh Thomas <[email protected]> (maintainer)
 
-[unreleased]: https://github.com/joshuadavidthomas/django-github-app/compare/v0.8.0...HEAD
+[unreleased]: https://github.com/joshuadavidthomas/django-github-app/compare/v0.9.0...HEAD
 [0.1.0]: https://github.com/joshuadavidthomas/django-github-app/releases/tag/v0.1.0
 [0.2.0]: https://github.com/joshuadavidthomas/django-github-app/releases/tag/v0.2.0
 [0.2.1]: https://github.com/joshuadavidthomas/django-github-app/releases/tag/v0.2.1
@@ -134,3 +136,4 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 [0.6.1]: https://github.com/joshuadavidthomas/django-github-app/releases/tag/v0.6.1
 [0.7.0]: https://github.com/joshuadavidthomas/django-github-app/releases/tag/v0.7.0
 [0.8.0]: https://github.com/joshuadavidthomas/django-github-app/releases/tag/v0.8.0
+[0.9.0]: https://github.com/joshuadavidthomas/django-github-app/releases/tag/v0.9.0