PowerShell: Update every list item in SharePoint

So I do have a workflow that starts, when an item has been changed. And i got a list with many items, which need an update to get the workflow started. Instead of clicking on every item, I decided to write a little script, to create an update on every item.

$web=get-SPWeb "YOURWEB"
$list=$web.Lists["YOURLIST"]
$list.title
foreach($item in $list.Items)
{
$item.update()
}
$web.dispose()

And now the workflow will run for every item.