Specify --locked to ensure reproducibility

Needed to stop mass-errors for us mortals without the latest rust version, ever since redox_syscall 0.1.57 was merged.

recipes/orbutils/recipe.toml

@@ -7,6 +7,7 @@ script = """
 COOKBOOK_CARGO_FLAGS=(
     --path "${COOKBOOK_SOURCE}"
     --root "${COOKBOOK_STAGE}/ui"
+    --locked
 )
 cookbook_cargo
 """