Enable extra build dependencies to 'match runtime' versions (#15036)
## Summary
This is an alternative to https://github.com/astral-sh/uv/pull/14944
that functions a little differently. Rather than adding separate
strategies, you can instead say:
```toml
[tool.uv.extra-build-dependencies]
child = [{ requirement = "anyio", match-runtime = true }]
```
Which will then enforce that `anyio` uses the same version as in the
lockfile.
