fix(deps): update dependency postcss to v8.4.21 (#8803)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

examples/front-end/advanced/babel-optimized/package.json

@@ -38,7 +38,7 @@
     "jest-resolve": "27.5.1",
     "jest-watch-typeahead": "1.1.0",
     "mini-css-extract-plugin": "2.7.2",
-    "postcss": "8.4.20",
+    "postcss": "8.4.21",
     "postcss-flexbugs-fixes": "5.0.2",
     "postcss-loader": "6.2.1",
     "postcss-normalize": "10.0.1",

examples/front-end/advanced/babel-optimized/yarn.lock

@@ -8423,10 +8423,10 @@ postcss-value-parser@^4.0.0, postcss-value-parser@^4.1.0, postcss-value-parser@^
   resolved "https://registry.yarnpkg.com/postcss-value-parser/-/postcss-value-parser-4.2.0.tgz#723c09920836ba6d3e5af019f92bc0971c02e514"
   integrity sha512-1NNCs6uurfkVbeXG4S8JFT9t19m45ICnif8zWLd5oPSZ50QnwMfK+H3jv408d4jw/7Bttv5axS5IiHoLaVNHeQ==
 
-[email protected].20, postcss@^8.3.5, postcss@^8.4.18, postcss@^8.4.19:
-  version "8.4.20"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.20.tgz#64c52f509644cecad8567e949f4081d98349dc56"
-  integrity sha512-6Q04AXR1212bXr5fh03u8aAwbLxAQNGQ/Q1LNa0VfOI06ZAlhPHtQvE4OIdpj4kLThXilalPnmDSOD65DcHt+g==
+[email protected].21, postcss@^8.3.5, postcss@^8.4.18, postcss@^8.4.19:
+  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"