fix files inclusion in sdist and wheel

pyproject.toml

@@ -82,8 +82,13 @@ distance-dirty = "{next_version}-dev{distance}+{vcs}{rev}.d{build_date:%Y%m%d}"
 [tool.versioningit.write]
 file = "mox/__version__.py"
 
+[tool.hatch.build.targets.sdist]
+packages = ["mox"]
+include = ["mox/**"]
+
 [tool.hatch.build.targets.wheel]
-packages = ["mox", "mox/testing"]
+packages = ["mox"]
+include = ["mox/**"]
 
 [tool.pytest.ini_options]
 addopts = [