Update version for v0.4.0 release

Author: github-actions

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "squeaky"
-version = "0.3.1"
+version = "0.4.0"
 description = "Remove noise from notebooks for cleaner version control diffs"
 readme = "README.md"
 requires-python = ">=3.7"