fix(testbed/cron): support nixos

scripts/testbed_cron.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 set -ex
 THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]:-${(%):-%x}}" )" && pwd )
 
@@ -46,7 +46,10 @@ update_key() {
 }
 
 main() {
-    cp "$THIS_DIR/nasp" "/etc/sudoers.d/nasp"
+    if [ -f /etc/os-release ]; then
+        . /etc/os-release
+        test "$ID" = "nixos" || cp "$THIS_DIR/nasp" "/etc/sudoers.d/nasp"
+    fi
     for file in "$THIS_DIR"/../authorized_keys/* ; do
         if [[ ! -d "$file" ]]; then
             continue