title: pubspec.yaml file has a newer timestamp
body: <p>I am using flutter to develop a previously created project. I have copied the project from another PC and copied it into my laptop. I have opened the project with vs code and in terminal I ran flutter packages get and after that when I ran flutter run I got this error  <code>pub did not update .packages file (pubspec.yaml file has a newer timestamp)</code> 
  any ideas?</p>