Can't use with Zig 0.13.0

When I use it with Zig 0.13.0, I get this error:

```
~/.cache/zig/p/12206dafe5c76efb352c28ca43c15d7033e8fb69ba1a1afd2ee2a8f9a52d31f39e9e/build.zig:13:33: error: no field named 'path' in union 'Build.LazyPath'
        .root_source_file = .{ .path = "src/ui.zig" },
```