chore(deps-dev): Bump postcss from 8.5.20 to 8.5.21 (#2027)

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Bumps [postcss](https://github.com/postcss/postcss) from 8.5.20 to
8.5.21.
<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>8.5.21</h2>
<ul>
<li>Fixed childless at-rule losing semicolon before comment (by <a
href="https://github.com/sarathfrancis90"><code>@​sarathfrancis90</code></a>).</li>
<li>Fixed docs (by <a
href="https://github.com/isker"><code>@​isker</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>8.5.21</h2>
<ul>
<li>Fixed childless at-rule losing semicolon before comment (by <a
href="https://github.com/sarathfrancis90"><code>@​sarathfrancis90</code></a>).</li>
<li>Fixed docs (by <a
href="https://github.com/isker"><code>@​isker</code></a>).</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/postcss/postcss/commit/28e0daf8f2fe5ba9e19ea3f8c27c8fe176f9419e"><code>28e0daf</code></a>
Release 8.5.21 version</li>
<li><a
href="https://github.com/postcss/postcss/commit/3d2b4e43e38274f233b5609d09687cadad8215d9"><code>3d2b4e4</code></a>
Update dependencies</li>
<li><a
href="https://github.com/postcss/postcss/commit/d197327e82e1a7d6dd9272effa3e4bfa91fdd20e"><code>d197327</code></a>
Fix childless at-rule losing its semicolon before a comment (<a
href="https://redirect.github.com/postcss/postcss/issues/2115">#2115</a>)</li>
<li><a
href="https://github.com/postcss/postcss/commit/0e360b749aa17a5a89baccf9c8e5db3c2978c21e"><code>0e360b7</code></a>
Fix mismatched JSDoc comments on Position (<a
href="https://redirect.github.com/postcss/postcss/issues/2114">#2114</a>)</li>
<li>See full diff in <a
href="https://github.com/postcss/postcss/compare/8.5.20...8.5.21">compare
view</a></li>
</ul>
</details>
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package-lock.json

@@ -100,7 +100,7 @@
         "istanbul": "^0.4.5",
         "istanbul-lib-coverage": "^3.2.2",
         "nyc": "^18.0.0",
-        "postcss": "^8.5.20",
+        "postcss": "^8.5.21",
         "react-hot-loader": "^4.13.1",
         "sass": "^1.101.3",
         "stylelint": "^17.14.1",
@@ -10742,9 +10742,9 @@
       }
     },
     "node_modules/postcss": {
-      "version": "8.5.20",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.20.tgz",
-      "integrity": "sha512-lW616l85ucIQL+FocMmL7pQFPqBmwejrCMg+iPxyImlrANNJG9NHq/RkyCZopDhd8C3LA03PHRJDjkbGu8vvug==",
+      "version": "8.5.21",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.21.tgz",
+      "integrity": "sha512-v4sDNP3fdNiWMfabO7OwOQdOX8TiQSztKyT1Wj0w+j7LDallJThJRBBBmzVGyYj0crMh7jlV4zepPkiNu9UwDQ==",
       "dev": true,
       "funding": [
         {

package.json

@@ -134,7 +134,7 @@
     "istanbul": "^0.4.5",
     "istanbul-lib-coverage": "^3.2.2",
     "nyc": "^18.0.0",
-    "postcss": "^8.5.20",
+    "postcss": "^8.5.21",
     "react-hot-loader": "^4.13.1",
     "sass": "^1.101.3",
     "stylelint": "^17.14.1",