Test the uv with old style dev dependencies sections

[nathanjmcdougall]

Motivation
This tool.uv.dev-dependencies section and tool.uv.dependency-groups.dev would, I think, not be recommended anymore, in favour of dependency-groups. But I'm not sure if there is a formal deprecation or anything so we should test this. If it's formally deprecated we should surface the deprecation warning (and that's probably a more general point; we should be surfacing all uv warnings to the user if possible #358). If support is already dropped, we should also drop support.

Summary of desired enhancement
Test with old-style dev dependencies sections