build(rust): vendor rnix parser crate

third_party/BUILD

@@ -1,4 +1,4 @@
-load("@rules_rust//crate_universe:defs.bzl", "crates_vendor")
+load("@rules_rust//crate_universe:defs.bzl", "crate", "crates_vendor")
 
 sh_binary(
     name = "bazel_for_cargo_bazel",
@@ -10,6 +10,11 @@ crates_vendor(
     bazel = ":bazel_for_cargo_bazel",
     cargo_lockfile = "//:Cargo.lock",
     manifests = ["//:Cargo.toml"],
+    packages = {
+        "rnix": crate.spec(
+            version = "=0.14.0",
+        ),
+    },
     mode = "local",
     tags = ["manual"],
     vendor_path = "crates",