title: when I hit yarn run dev . it shows 'next' is not recognized as an internal or external command, operable program or batch file
body: <p>I've installed <code>yarn create next-app my-app</code>. Then when I tried to run this command <code>yarn dev</code> It shows the error <code>next is not recognized as an internal or external command</code>, operable program or batch file.</p>
  <p>Please provide the solution. I've already spent the whole day to fix this :(</p>