Release v0.4.0 (#226)

* Fix suggested change of changelog in CONTRIBUING.md
* Update version to 0.4.0 in pyproject.toml
* Add header for version 0.4.0 in changelog

Author: ValerianRey

CHANGELOG.md

@@ -8,6 +8,8 @@ changes that do not affect the user.
 
 ## [Unreleased]
 
+## [0.4.0] - 2025-01-02
+
 ### Changed
 
 - Changed how the Jacobians are computed when calling `backward` or `mtl_backward` with

CONTRIBUTING.md

@@ -98,7 +98,7 @@ To release a new `torchjd` version, you have to:
 - Make sure that all important changes since the last release have been reported in the
   `[Unreleased]`
   section at the top of the changelog.
-- Change the `[Unreleased]` section to a `[vX.Y.Z]` section in the changelog with the current date.
+- Add a `[X.Y.Z] - yyyy-mm-dd` header in the changelog just below the `[Unreleased]` header.
 - Change the version in `pyproject.toml`.
 - Make a pull request with those changes and merge it.
 - Make a draft of the release on GitHub (click on `Releases`, then `Draft a new release`, then fill

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "pdm.backend"
 
 [project]
 name = "torchjd"
-version = "0.3.1"
+version = "0.4.0"
 description = "Library for Jacobian Descent with PyTorch."
 readme = "README.md"
 authors = [