chore: Update rust-build-sysroot

The previous version (0.5.2), in combination with the latest Rust
nightly, fails to build the sysroot with the following error:

```
---- compile_test stdout ----
thread 'compile_test' panicked at tests/tests.rs:130:10:
failed to build sysroot: failed to copy lockfile from sysroot source
```

This error is related to rust-lang/rust#128534, which moved the standard
library to a separate workspace, therefore moving `Cargo.lock` as well.
RalfJung/rustc-build-sysroot#22 honors the new location. That change
was released in 0.5.3.

Cargo.toml

@@ -36,7 +36,7 @@ tracing = "0.1"
 [dev-dependencies]
 compiletest_rs = { version = "0.10.1" }
 regex = { version = "1.10.5", default-features = false }
-rustc-build-sysroot = { version = "0.5.2", default-features = false }
+rustc-build-sysroot = { version = "0.5.3", default-features = false }
 which = { version = "6.0.1", default-features = false, features = ["regex"] }
 
 [[bin]]