pyproject.toml: explicitly select packages to search for

Fixes #15

pyproject.toml

@@ -35,5 +35,8 @@ api = ["python-gitlab>=4.0.0"]
 [project.urls]
 Homepage = "https://www.postmarketos.org"
 
+[tool.setuptools.packages.find]
+include = ["mrhlpr*", "mrtest*"]
+
 [tool.ruff]
 line-length=100