title: npm postinstall script - execute script from dependency
body: <p>sadly I can't find anything on this issue except for some stuff from 4 years ago.</p>
  
  <p>Suppose I have 2 packages: <code>@my/package</code> and <code>@my/parent</code>.</p>
  
  <p>Now in <code>@my/parent</code> I'm trying to use a postinstall script like this:
  <code>postinstall: "node ./node_modules/@my/package/dist/postinstall.js"</code></p>
  
  <p>This will always fail though, because apparently at the time that the postinstall script is being called, the script file is not present.</p>
  
  <p>Is it supposed to be like that? Aren't you able to call scripts from dependencies in postinstall?</p>
  
  <p>Thanks in advance.</p>
  
  <p>Cheers</p>