Use correct target_base for unpacking

In #2, we accidentally changed the `target_base` from the target base to the parent of the file. This would cause hardlink unpacking to fail.

Example: A hardlink at `hardlinked-0.1.0/pyproject.toml` pointing to `hardlinked-0.1.0/pyproject.toml.real` would try pointing to `hardlinked-0.1.0/`hardlinked-0.1.0/pyproject.toml.real` instead and fail the unpacking.

[future edit: uv companion PR with test]

Author: konstin

src/entry.rs

@@ -516,7 +516,7 @@ impl<R: Read + Unpin> EntryFields<R> {
             memo.insert(parent.to_path_buf());
         }
 
-        self.unpack(Some(&parent), &file_dst)
+        self.unpack(Some(&dst), &file_dst)
             .await
             .map_err(|e| TarError::new(&format!("failed to unpack `{}`", file_dst.display()), e))?;