set release date for v0.6.0

Author: tobiasraabe

CHANGELOG.md

@@ -5,7 +5,7 @@ chronological order. Releases follow [semantic versioning](https://semver.org/)
 releases are available on [PyPI](https://pypi.org/project/pytask) and
 [Anaconda.org](https://anaconda.org/conda-forge/pytask).
 
-## Unreleased
+## 0.6.0 - 2026-05-01
 
 - [#875](https://github.com/pytask-dev/pytask/pull/875) improves the documentation
   homepage cards by making the full tile clickable and fixes the plugin list warning