specify exported api methods in __all__

It's py.types requirement, similar to 6e2edbf

Example issue without __all__:
import ifcopenshell
import ifcopenshell.api.project

# "create_file" is not exported from module "ifcopenshell.api.project"
ifcopenshell.api.project.create_file()

src/ifcopenshell-python/ifcopenshell/api/georeference/__init__.py

@@ -29,3 +29,9 @@ from .edit_georeferencing import edit_georeferencing
 from .remove_georeferencing import remove_georeferencing
 
 wrap_usecases(__path__, __name__)
+
+__all__ = [
+    "add_georeferencing",
+    "edit_georeferencing",
+    "remove_georeferencing",
+]