Read ../README.md

[astrojuanlu]

Is there a way to use an out-of-tree ../README.md as the readme = {file = }?

I've tried the obvious but it produces a sdist that cannot be installed because it contains an invalid path.

I have also tried using a metadata hook but I can't reach ../README.md through self.root because the temporary directory doesn't have it.

Context: kedro-org/kedro-viz#1766