Bump postcss from 8.4.19 to 8.4.20 in /dashboard (#5811)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.19 to
8.4.20.
<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>8.4.20</h2>
<ul>
<li>Fixed source map generation for childless at-rules like
<code>@layer</code>.</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>8.4.20</h2>
<ul>
<li>Fixed source map generation for childless at-rules like
<code>@layer</code>.</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/postcss/postcss/commit/1d4c509c114a0dd8270cb5241c5eee7d01f91674"><code>1d4c509</code></a>
Release 8.4.20 version</li>
<li><a
href="https://github.com/postcss/postcss/commit/905082a5c1a0246e9187d5c8535ad5c576c18365"><code>905082a</code></a>
Add Node.js 10 to CI</li>
<li><a
href="https://github.com/postcss/postcss/commit/20122e50b707b52f13a03db0310adc4e5a9c8650"><code>20122e5</code></a>
Fix childless at-rule map generation</li>
<li><a
href="https://github.com/postcss/postcss/commit/ff7e8ce09749fa1f7451d6d69f5677a14c0f6fc6"><code>ff7e8ce</code></a>
Merge pull request <a
href="https://github-redirect.dependabot.com/postcss/postcss/issues/1801">#1801</a>
from romainmenke/invalid-sourcemap-with-at-layer--pr...</li>
<li><a
href="https://github.com/postcss/postcss/commit/d585976fc1e09f81f59fd0e3f3ef908b3dc87273"><code>d585976</code></a>
Fix CI</li>
<li><a
href="https://github.com/postcss/postcss/commit/744b15f8c507a9a7d1a92a94752b4926bce12f82"><code>744b15f</code></a>
Update dependencies</li>
<li><a
href="https://github.com/postcss/postcss/commit/db935f19f067bb0db2121a31b4dfd429f7e5a889"><code>db935f1</code></a>
invalid sourcemap with at layer</li>
<li><a
href="https://github.com/postcss/postcss/commit/3cac84ae46a5f4427393cce549af5fd9f343e837"><code>3cac84a</code></a>
Fix type tests</li>
<li><a
href="https://github.com/postcss/postcss/commit/5113edb7a297fa6ec1e6d55b71d0e5a1d1f217d5"><code>5113edb</code></a>
Update dependencies</li>
<li>See full diff in <a
href="https://github.com/postcss/postcss/compare/8.4.19...8.4.20">compare
view</a></li>
</ul>
</details>
<br />


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Signed-off-by: dependabot[bot] <support@github.com>
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dashboard/package.json

@@ -104,7 +104,7 @@
     "monaco-editor-webpack-plugin": "^7.0.1",
     "node-polyfill-webpack-plugin": "^2.0.1",
     "npm-run-all": "^4.1.5",
-    "postcss": "^8.4.19",
+    "postcss": "^8.4.20",
     "postcss-scss": "^4.0.6",
     "prettier": "^2.8.1",
     "react-dom": "^17.0.2",

dashboard/yarn.lock

@@ -10732,10 +10732,10 @@ postcss@^7.0.35:
     picocolors "^0.2.1"
     source-map "^0.6.1"
 
-postcss@^8.3.11, postcss@^8.3.5, postcss@^8.4.18, postcss@^8.4.19, postcss@^8.4.4:
-  version "8.4.19"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.19.tgz#61178e2add236b17351897c8bcc0b4c8ecab56fc"
-  integrity sha512-h+pbPsyhlYj6N2ozBmHhHrs9DzGmbaarbLvWipMRO7RLS+v4onj26MPFXA5OBYFxyqYhUJK456SwDcY9H2/zsA==
+postcss@^8.3.11, postcss@^8.3.5, postcss@^8.4.18, postcss@^8.4.19, postcss@^8.4.20, postcss@^8.4.4:
+  version "8.4.20"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.20.tgz#64c52f509644cecad8567e949f4081d98349dc56"
+  integrity sha512-6Q04AXR1212bXr5fh03u8aAwbLxAQNGQ/Q1LNa0VfOI06ZAlhPHtQvE4OIdpj4kLThXilalPnmDSOD65DcHt+g==
   dependencies:
     nanoid "^3.3.4"
     picocolors "^1.0.0"