$ pip install -e .
Obtaining file:///Users/akx/build/openapi2jsonschema
Installing build dependencies ... done
Checking if build backend supports build_editable ... done
ERROR: Project file:///Users/akx/build/openapi2jsonschema has a 'pyproject.toml' and its build backend is missing the 'build_editable' hook. Since it does not have a 'setup.py' nor a 'setup.cfg', it cannot be installed in editable mode. Consider using a build backend that supports PEP 660.
Before:
After: