title: Error: PostCSS plugin autoprefixer requires PostCSS 8. Update PostCSS or downgrade this plugin
body: <p>I am getting this error whenever I run npm start.
  I tried a couple of fixes but none of them work for me. I tried to change the version of autoprefixer to 9.8.6 but it didn't work.
  Please help me with this issue</p>
  <p>This is my package.json</p>
  <pre><code>{
    &quot;name&quot;: &quot;reactgallery&quot;,
    &quot;version&quot;: &quot;0.1.0&quot;,
    &quot;private&quot;: true,
    &quot;dependencies&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;react&quot;: &quot;^16.13.1&quot;,
      &quot;react-dom&quot;: &quot;^16.13.1&quot;,
      &quot;react-scripts&quot;: &quot;3.4.3&quot;
    },
    &quot;scripts&quot;: {
      &quot;start&quot;: &quot;npm run watch:css &amp;&amp; react-scripts start&quot;,
      &quot;build&quot;: &quot;npm run build:css &amp;&amp; react-scripts build&quot;,
      &quot;test&quot;: &quot;react-scripts test&quot;,
      &quot;eject&quot;: &quot;react-scripts eject&quot;,
      &quot;build:css&quot;: &quot;postcss src/assets/tailwind.css -o src/assets/main.css&quot;,
      &quot;watch:css&quot;: &quot;postcss src/assets/tailwind.css -o src/assets/main.css&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;autoprefixer&quot;: &quot;^9.8.6&quot;,
      &quot;postcss-cli&quot;: &quot;^7.1.2&quot;,
      &quot;tailwindcss&quot;: &quot;^1.8.10&quot;
    }
  }
  </code></pre>