Prepare release v0.2.1 (#198)

## heroku/dotnet

### Changed

- The .NET SDK inventory was updated with new download URLs for version 9.0 release artifacts. [#197](#197)

### Added

- Support for .NET SDK versions: 8.0.113 (linux-amd64), 8.0.113 (linux-arm64), 8.0.309 (linux-amd64), 8.0.309 (linux-arm64), 8.0.406 (linux-amd64), 8.0.406 (linux-arm64), 9.0.103 (linux-amd64), 9.0.103 (linux-arm64), 9.0.200 (linux-amd64), 9.0.200 (linux-arm64). [#197](#197)

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

buildpacks/dotnet/CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.2.1] - 2025-02-12
+
 ### Changed
 
 - The .NET SDK inventory was updated with new download URLs for version 9.0 release artifacts. [#197](https://github.com/heroku/buildpacks-dotnet/pull/197)
@@ -101,7 +103,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Initial implementation.
 
-[unreleased]: https://github.com/heroku/buildpacks-dotnet/compare/v0.2.0...HEAD
+[unreleased]: https://github.com/heroku/buildpacks-dotnet/compare/v0.2.1...HEAD
+[0.2.1]: https://github.com/heroku/buildpacks-dotnet/compare/v0.2.0...v0.2.1
 [0.2.0]: https://github.com/heroku/buildpacks-dotnet/compare/v0.1.10...v0.2.0
 [0.1.10]: https://github.com/heroku/buildpacks-dotnet/compare/v0.1.9...v0.1.10
 [0.1.9]: https://github.com/heroku/buildpacks-dotnet/compare/v0.1.8...v0.1.9

buildpacks/dotnet/buildpack.toml

@@ -2,7 +2,7 @@ api = "0.10"
 
 [buildpack]
 id = "heroku/dotnet"
-version = "0.2.0"
+version = "0.2.1"
 name = "Heroku .NET"
 homepage = "https://github.com/heroku/buildpacks-dotnet"
 description = "Heroku's buildpack for .NET applications."