smart mode is broken if pyproject.toml exists in project

[lovetox]

smart mode seems to depend on the parse_pyproject_toml() returning an empty dict

But parse_pyproject_toml() never returns an empty dict, if pyproject.toml exists, because even if no black key is found in pyproject.toml and the dict would be indeed empty, it adds a target_version key after.

i would make a PR but it seems not straight forward whats the best solution here

Ideas i had:

• return also a bool that signals if the black key was found in the config?
• pass the smart mode as argument to parse_pyproject_toml(), and return before target version is added
• parse the black dict from pyproject into a black key into the config dict, that would allow the following code to check if the black key is empty, but would make code later which access the config a bit less pretty