Prepare release v0.15.0 (#246)

## heroku/python

### Changed

- Updated the default Python version from 3.12.4 to 3.12.5. ([#244](#244))
- Updated pip from 24.1.2 to 24.2. ([#236](#236))

Co-authored-by: heroku-linguist[bot] <136119646+heroku-linguist[bot]@users.noreply.github.com>

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]
 
+## [0.15.0] - 2024-08-07
+
 ### Changed
 
 - Updated the default Python version from 3.12.4 to 3.12.5. ([#244](https://github.com/heroku/buildpacks-python/pull/244))
@@ -180,7 +182,8 @@ 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/v0.14.0...HEAD
+[unreleased]: https://github.com/heroku/buildpacks-python/compare/v0.15.0...HEAD
+[0.15.0]: https://github.com/heroku/buildpacks-python/compare/v0.14.0...v0.15.0
 [0.14.0]: https://github.com/heroku/buildpacks-python/compare/v0.13.0...v0.14.0
 [0.13.0]: https://github.com/heroku/buildpacks-python/compare/v0.12.1...v0.13.0
 [0.12.1]: https://github.com/heroku/buildpacks-python/compare/v0.12.0...v0.12.1

buildpack.toml

@@ -2,7 +2,7 @@ api = "0.10"
 
 [buildpack]
 id = "heroku/python"
-version = "0.14.0"
+version = "0.15.0"
 name = "Heroku Python"
 homepage = "https://github.com/heroku/buildpacks-python"
 description = "Heroku's buildpack for Python applications."