chore(deps): Bump postcss from 8.4.27 to 8.4.31 in /demo/frontend (#920)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.27 to
8.4.31.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/postcss/postcss/releases">postcss's
releases</a>.</em></p>
<blockquote>
<h2>8.4.31</h2>
<ul>
<li>Fixed <code>\r</code> parsing to fix CVE-2023-44270.</li>
</ul>
<h2>8.4.30</h2>
<ul>
<li>Improved source map performance (by <a
href="https://github.com/romainmenke"><code>@​romainmenke</code></a>).</li>
</ul>
<h2>8.4.29</h2>
<ul>
<li>Fixed <code>Node#source.offset</code> (by <a
href="https://github.com/idoros"><code>@​idoros</code></a>).</li>
<li>Fixed docs (by <a
href="https://github.com/coliff"><code>@​coliff</code></a>).</li>
</ul>
<h2>8.4.28</h2>
<ul>
<li>Fixed <code>Root.source.end</code> for better source map (by <a
href="https://github.com/romainmenke"><code>@​romainmenke</code></a>).</li>
<li>Fixed <code>Result.root</code> types when <code>process()</code> has
no parser.</li>
</ul>
</blockquote>
</details>
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a
href="https://github.com/postcss/postcss/blob/main/CHANGELOG.md">postcss's
changelog</a>.</em></p>
<blockquote>
<h2>8.4.31</h2>
<ul>
<li>Fixed <code>\r</code> parsing to fix CVE-2023-44270.</li>
</ul>
<h2>8.4.30</h2>
<ul>
<li>Improved source map performance (by Romain Menke).</li>
</ul>
<h2>8.4.29</h2>
<ul>
<li>Fixed <code>Node#source.offset</code> (by Ido Rosenthal).</li>
<li>Fixed docs (by Christian Oliff).</li>
</ul>
<h2>8.4.28</h2>
<ul>
<li>Fixed <code>Root.source.end</code> for better source map (by Romain
Menke).</li>
<li>Fixed <code>Result.root</code> types when <code>process()</code> has
no parser.</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="90208de880"><code>90208de</code></a>
Release 8.4.31 version</li>
<li><a
href="58cc860b4c"><code>58cc860</code></a>
Fix carrier return parsing</li>
<li><a
href="4fff8e4cdc"><code>4fff8e4</code></a>
Improve pnpm test output</li>
<li><a
href="cd43ed1232"><code>cd43ed1</code></a>
Update dependencies</li>
<li><a
href="caa916bdcb"><code>caa916b</code></a>
Update dependencies</li>
<li><a
href="8972f76923"><code>8972f76</code></a>
Typo</li>
<li><a
href="11a5286f78"><code>11a5286</code></a>
Typo</li>
<li><a
href="45c5501777"><code>45c5501</code></a>
Release 8.4.30 version</li>
<li><a
href="bc3c341f58"><code>bc3c341</code></a>
Update linter</li>
<li><a
href="b2be58a2eb"><code>b2be58a</code></a>
Merge pull request <a
href="https://redirect.github.com/postcss/postcss/issues/1881">#1881</a>
from romainmenke/improve-sourcemap-performance--phil...</li>
<li>Additional commits viewable in <a
href="https://github.com/postcss/postcss/compare/8.4.27...8.4.31">compare
view</a></li>
</ul>
</details>
<br />


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demo/frontend/yarn.lock

@@ -3593,9 +3593,9 @@ postcss-value-parser@^4.0.2:
   integrity sha512-1NNCs6uurfkVbeXG4S8JFT9t19m45ICnif8zWLd5oPSZ50QnwMfK+H3jv408d4jw/7Bttv5axS5IiHoLaVNHeQ==
 
 postcss@^8.4.27:
-  version "8.4.27"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.27.tgz#234d7e4b72e34ba5a92c29636734349e0d9c3057"
-  integrity sha512-gY/ACJtJPSmUFPDCHtX78+01fHa64FaU4zaaWfuh1MhGJISufJAH4cun6k/8fwsHYeK4UQmENQK+tRLCFJE8JQ==
+  version "8.4.31"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.31.tgz#92b451050a9f914da6755af352bdc0192508656d"
+  integrity sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==
   dependencies:
     nanoid "^3.3.6"
     picocolors "^1.0.0"