Bump postcss from 8.4.20 to 8.4.21 (#23019)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.20 to 8.4.21.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.4.20...8.4.21)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -84,7 +84,7 @@
     "object.values": "^1.1.6",
     "path-complete-extname": "^1.0.0",
     "pg": "^8.5.0",
-    "postcss": "^8.4.20",
+    "postcss": "^8.4.21",
     "postcss-loader": "^3.0.0",
     "promise.prototype.finally": "^3.1.4",
     "prop-types": "^15.8.1",

yarn.lock

@@ -8513,10 +8513,10 @@ postcss@^7.0.0, postcss@^7.0.1, postcss@^7.0.27, postcss@^7.0.32:
     source-map "^0.6.1"
     supports-color "^6.1.0"
 
-postcss@^8.2.15, postcss@^8.4.19, postcss@^8.4.20:
-  version "8.4.20"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.20.tgz#64c52f509644cecad8567e949f4081d98349dc56"
-  integrity sha512-6Q04AXR1212bXr5fh03u8aAwbLxAQNGQ/Q1LNa0VfOI06ZAlhPHtQvE4OIdpj4kLThXilalPnmDSOD65DcHt+g==
+postcss@^8.2.15, postcss@^8.4.19, postcss@^8.4.21:
+  version "8.4.21"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.21.tgz#c639b719a57efc3187b13a1d765675485f4134f4"
+  integrity sha512-tP7u/Sn/dVxK2NnruI4H9BG+x+Wxz6oeZ1cJ8P6G/PZY0IKk4k/63TDsQf2kQq3+qoJeLm2kIBUNlZe3zgb4Zg==
   dependencies:
     nanoid "^3.3.4"
     picocolors "^1.0.0"