chore(deps-dev): Bump postcss from 8.5.19 to 8.5.20 (#2021)

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.19 to
8.5.20.
<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>8.5.20</h2>
<ul>
<li>Fixed missing space if <code>AtRule#params</code> is set after (by
<a
href="https://github.com/sarathfrancis90"><code>@​sarathfrancis90</code></a>).</li>
<li>Fixed mixing AST error on warnings (by <a
href="https://github.com/MahinAnowar"><code>@​MahinAnowar</code></a>).</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>8.5.20</h2>
<ul>
<li>Fixed missing space if <code>AtRule#params</code> is set after (by
<a
href="https://github.com/sarathfrancis90"><code>@​sarathfrancis90</code></a>).</li>
<li>Fixed mixing AST error on warnings (by <a
href="https://github.com/MahinAnowar"><code>@​MahinAnowar</code></a>).</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/postcss/postcss/commit/c4ac725d5920916d35be44002b49b7f66f8b1dc8"><code>c4ac725</code></a>
Release 8.5.20 version</li>
<li><a
href="https://github.com/postcss/postcss/commit/c30586d7863d0563e2f2707bd89461636e37f6f6"><code>c30586d</code></a>
Fix missing space when AtRule#params is set after parsing (<a
href="https://redirect.github.com/postcss/postcss/issues/2113">#2113</a>)</li>
<li><a
href="https://github.com/postcss/postcss/commit/5bfc3b9e7463936fdd4898f92dd43c358bfdef62"><code>5bfc3b9</code></a>
Update dependencies</li>
<li><a
href="https://github.com/postcss/postcss/commit/24733fdbfe9abe4a949eb0a10e53db8c87fc9277"><code>24733fd</code></a>
Move back to latest 11 pnpm</li>
<li><a
href="https://github.com/postcss/postcss/commit/728127c427e076ae15f4b4107cae29f9e60d2db4"><code>728127c</code></a>
Update pnpm to check that CI is fixed</li>
<li><a
href="https://github.com/postcss/postcss/commit/806fe21198e210cc85fd87d4afd0c949b04e0c1f"><code>806fe21</code></a>
Rebuild nodes from another PostCSS copy in Warning (<a
href="https://redirect.github.com/postcss/postcss/issues/2112">#2112</a>)</li>
<li><a
href="https://github.com/postcss/postcss/commit/337cb7ef092da6066ec845973af243ed8e378550"><code>337cb7e</code></a>
Improve CI security</li>
<li><a
href="https://github.com/postcss/postcss/commit/7a8ca2d0e5044fbde3df33e2b9730c14528270e3"><code>7a8ca2d</code></a>
Remove patch after updating dependency</li>
<li>See full diff in <a
href="https://github.com/postcss/postcss/compare/8.5.19...8.5.20">compare
view</a></li>
</ul>
</details>
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package.json

@@ -134,7 +134,7 @@
     "istanbul": "^0.4.5",
     "istanbul-lib-coverage": "^3.2.2",
     "nyc": "^18.0.0",
-    "postcss": "^8.5.19",
+    "postcss": "^8.5.20",
     "react-hot-loader": "^4.13.1",
     "sass": "^1.101.0",
     "stylelint": "^17.14.0",