Fix multiple top level packages (#1006)

pyproject.toml

@@ -13,10 +13,13 @@ exclude = [
     "configs",
     "notebooks"
 ]
+packages = [
+    { include = "embedchain" },
+]
 
 [build-system]
-requires = ["setuptools", "wheel"]
-build-backend = "setuptools.build_meta"
+build-backend = "poetry.core.masonry.api"
+requires = ["poetry-core"]
 
 [tool.ruff]
 select = ["E", "F"]