title: create-react-app is deployed on Heroku but page is blank
body: <p>I'm trying to deploy a <code>react</code> app on <code>heroku</code> but after deploying it on heroku its showing blank page,I've also created this app using <code>buildpack mars/create-react-app</code></p>
  <p>This is what I'm getting on deployed project:</p>
  <p><img src="https://i.stack.imgur.com/Od5m3.png" alt="This is what I'm getting on deployed project" /></p>
  <p>Here's my <code>package.json</code> file:</p>
  <pre class="lang-js prettyprint-override"><code>    {
        &quot;name&quot;: &quot;covid-19&quot;,
        &quot;version&quot;: &quot;0.1.0&quot;,
        &quot;private&quot;: true,
        &quot;homepage&quot;: &quot;covid-19-stats-by-anny-v3&quot;,
        &quot;dependencies&quot;: {
          &quot;@material-ui/core&quot;: &quot;^4.11.0&quot;,
          &quot;@material-ui/icons&quot;: &quot;^4.9.1&quot;,
          &quot;@testing-library/jest-dom&quot;: &quot;^4.2.4&quot;,
          &quot;@testing-library/react&quot;: &quot;^9.5.0&quot;,
          &quot;@testing-library/user-event&quot;: &quot;^7.2.1&quot;,
          &quot;axios&quot;: &quot;^0.19.2&quot;,
          &quot;express&quot;: &quot;^4.17.1&quot;,
          &quot;fetch&quot;: &quot;^1.1.0&quot;,
          &quot;gh-pages&quot;: &quot;^3.1.0&quot;,
          &quot;material-table&quot;: &quot;^1.65.0&quot;,
          &quot;mui-datatables&quot;: &quot;^3.3.1&quot;,
          &quot;react&quot;: &quot;^16.13.1&quot;,
          &quot;react-dom&quot;: &quot;^16.13.1&quot;,
          &quot;react-social-icons&quot;: &quot;^4.1.0&quot;
        },
        &quot;scripts&quot;: {
          &quot;start&quot;: &quot;react-scripts start&quot;,
          &quot;predeploy&quot;: &quot;npm run build&quot;,
          &quot;build&quot;: &quot;react-scripts build&quot;,
          &quot;test&quot;: &quot;react-scripts test&quot;,
          &quot;eject&quot;: &quot;react-scripts eject&quot;
        },
        &quot;eslintConfig&quot;: {
          &quot;extends&quot;: &quot;react-app&quot;
        },
        &quot;browserslist&quot;: {
          &quot;production&quot;: [
            &quot;&gt;0.2%&quot;,
            &quot;not dead&quot;,
            &quot;not op_mini all&quot;
          ],
          &quot;development&quot;: [
            &quot;last 1 chrome version&quot;,
            &quot;last 1 firefox version&quot;,
            &quot;last 1 safari version&quot;
          ]
        },
        &quot;devDependencies&quot;: {
          &quot;react-scripts&quot;: &quot;^3.4.1&quot;
        }
      }
  </code></pre>