Prepare release v0.3.1

## heroku/dotnet

### Changed

- The .NET SDK inventory was updated with new download URLs for version 9.0 release artifacts. ([#203](#203))
- The buildpack will now skip NuGet package XML doc extraction when running `dotnet publish`. ([#212](#212))
- The build configuration is no longer written to the log before the `dotnet publish` command (which still includes the build configuration value when specified). ([#213](#213))

Author: heroku-linguist[bot]

buildpacks/dotnet/CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.3.1] - 2025-03-10
+
 ### Changed
 
 - The .NET SDK inventory was updated with new download URLs for version 9.0 release artifacts. ([#203](https://github.com/heroku/buildpacks-dotnet/pull/203))
@@ -122,7 +124,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Initial implementation.
 
-[unreleased]: https://github.com/heroku/buildpacks-dotnet/compare/v0.3.0...HEAD
+[unreleased]: https://github.com/heroku/buildpacks-dotnet/compare/v0.3.1...HEAD
+[0.3.1]: https://github.com/heroku/buildpacks-dotnet/compare/v0.3.0...v0.3.1
 [0.3.0]: https://github.com/heroku/buildpacks-dotnet/compare/v0.2.2...v0.3.0
 [0.2.2]: https://github.com/heroku/buildpacks-dotnet/compare/v0.2.1...v0.2.2
 [0.2.1]: https://github.com/heroku/buildpacks-dotnet/compare/v0.2.0...v0.2.1

buildpacks/dotnet/buildpack.toml

@@ -2,7 +2,7 @@ api = "0.10"
 
 [buildpack]
 id = "heroku/dotnet"
-version = "0.3.0"
+version = "0.3.1"
 name = "Heroku .NET"
 homepage = "https://github.com/heroku/buildpacks-dotnet"
 description = "Heroku's buildpack for .NET applications."