Prepare release v6.4.1

## heroku/python

### Changed

- Updated Poetry from 2.3.3 to 2.3.4. ([#553](#553))
- Updated uv from 0.11.3 to 0.11.6. ([#552](#552))

Author: heroku-linguist[bot]

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [6.4.1] - 2026-04-13
+
 ### Changed
 
 - Updated Poetry from 2.3.3 to 2.3.4. ([#553](https://github.com/heroku/buildpacks-python/pull/553))
@@ -634,7 +636,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Initial implementation. ([#3](https://github.com/heroku/buildpacks-python/pull/3))
 
-[unreleased]: https://github.com/heroku/buildpacks-python/compare/v6.4.0...HEAD
+[unreleased]: https://github.com/heroku/buildpacks-python/compare/v6.4.1...HEAD
+[6.4.1]: https://github.com/heroku/buildpacks-python/compare/v6.4.0...v6.4.1
 [6.4.0]: https://github.com/heroku/buildpacks-python/compare/v6.3.0...v6.4.0
 [6.3.0]: https://github.com/heroku/buildpacks-python/compare/v6.2.0...v6.3.0
 [6.2.0]: https://github.com/heroku/buildpacks-python/compare/v6.1.0...v6.2.0

buildpack.toml

@@ -2,7 +2,7 @@ api = "0.10"
 
 [buildpack]
 id = "heroku/python"
-version = "6.4.0"
+version = "6.4.1"
 name = "Heroku Python"
 homepage = "https://github.com/heroku/buildpacks-python"
 description = "Heroku's buildpack for Python applications."