title: NextJS: getStaticProps revalidate not working
body: <p>I have this NextJS site where there is this getStaticProps that load data from Firestore.</p>
  <p>I have this:</p>
  <pre><code>return {
      props: {
        allPosts: posts,
      },
      revalidate: 60,
    }
  </code></pre>
  <p>where from what I know will load data from firebase every one minute.  However, it doesn't seem to work and data are just not updated.</p>
  <p>Is this revalidate an experimental feature?  Anyway that I can get it to work?  Else I would have to rebuild and export frequently.</p>