Bump postcss from 8.4.21 to 8.4.31 in /frontend (#565)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.21 to 8.4.31.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.21...8.4.31)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:development
...

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

frontend/package.json

@@ -116,7 +116,7 @@
     "eslint-plugin-react": "7.33.0",
     "eslint-plugin-react-hooks": "4.6.0",
     "msw": "0.28.1",
-    "postcss": "8.4.21",
+    "postcss": "8.4.31",
     "prettier": "2.2.1",
     "setimmediate": "1.0.5"
   }

frontend/yarn.lock

@@ -7547,7 +7547,7 @@ mz@^2.7.0:
     object-assign "^4.0.1"
     thenify-all "^1.0.0"
 
-nanoid@^3.3.4, nanoid@^3.3.6:
+nanoid@^3.3.6:
   version "3.3.6"
   resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-3.3.6.tgz#443380c856d6e9f9824267d960b4236ad583ea4c"
   integrity sha512-BGcqMMJuToF7i1rt+2PWSNVnWIkGCU78jBG3RxO/bZlnZPK2Cmi2QaffxGO/2RvWi9sL+FAiRiXMgsyxQ1DIDA==
@@ -8499,12 +8499,12 @@ 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].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==
+[email protected].31, postcss@^8.3.5, postcss@^8.4.21, postcss@^8.4.23, postcss@^8.4.4:
+  version "8.4.31"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.31.tgz#92b451050a9f914da6755af352bdc0192508656d"
+  integrity sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==
   dependencies:
-    nanoid "^3.3.4"
+    nanoid "^3.3.6"
     picocolors "^1.0.0"
     source-map-js "^1.0.2"
 
@@ -8516,15 +8516,6 @@ postcss@^7.0.35:
     picocolors "^0.2.1"
     source-map "^0.6.1"
 
-postcss@^8.3.5, postcss@^8.4.21, postcss@^8.4.23, postcss@^8.4.4:
-  version "8.4.27"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.27.tgz#234d7e4b72e34ba5a92c29636734349e0d9c3057"
-  integrity sha512-gY/ACJtJPSmUFPDCHtX78+01fHa64FaU4zaaWfuh1MhGJISufJAH4cun6k/8fwsHYeK4UQmENQK+tRLCFJE8JQ==
-  dependencies:
-    nanoid "^3.3.6"
-    picocolors "^1.0.0"
-    source-map-js "^1.0.2"
-
 prelude-ls@^1.2.1:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.2.1.tgz#debc6489d7a6e6b0e7611888cec880337d316396"