`path` dependencies in `[patch.crates-io]` used in cargo_universe resolve relative paths incorrectly

When using a crates_universe setup, a `Cargo.toml` includes

```
[patch.crates-io]
foo = { path = "../foo" }
```

This specifies that we should locate `foo` in the parent directory of the dir containing the `Cargo.toml` including this line.

rules_rust instead appears to treat this path as relative to some temporary directory (in `/tmp`, at least on linux) and complains about not finding a package at `/tmp/foo` when `cargo-bazel splice` is executed.