explicitly denoting top-level package directory for setuptools (to fix installation error)

Author: cmendl

pyproject.toml

@@ -3,7 +3,7 @@ name = "fermi_relations"
 version = "0.0.1"
 readme = { file = "README.rst", content-type = "text/x-rst" }
 authors = [{ name = "Christian B. Mendl", email = "christian.b.mendl@gmail.com" }]
-license = { file = "LICENSE" }
+license = "Apache-2.0"
 requires-python = ">=3.10"
 dependencies = [
     "numpy",
@@ -18,3 +18,6 @@ issues = "https://github.com/cmendl/fermi_relations/issues"
 [build-system]
 requires = ["setuptools"]
 build-backend = "setuptools.build_meta"
+
+[tool.setuptools]
+packages = ["fermi_relations"]