build: replace true with a custom noop script

`true` might be a shell built-in, or simply not accessible in the hardcoded locations.
Replace it with a custom script that does nothing.

Signed-off-by: Ilya Katsnelson <me@0upti.me>

scripts/noop.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+# This script does nothing, intentionally.