chore(deps): update dependency postcss to v8.4.12 (#763)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

frontend/package.json

@@ -34,7 +34,7 @@
     "mini-css-extract-plugin": "2.6.0",
     "mustache": "4.2.0",
     "node-sass": "7.0.1",
-    "postcss": "8.4.8",
+    "postcss": "8.4.12",
     "postcss-loader": "6.2.1",
     "postcss-preset-env": "7.4.2",
     "preact": "10.6.6",

yarn.lock

@@ -13163,10 +13163,10 @@ postcss-values-parser@^2.0.1:
     indexes-of "^1.0.1"
     uniq "^1.0.1"
 
-postcss@8.4.8, postcss@^8.4.7:
-  version "8.4.8"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.8.tgz#dad963a76e82c081a0657d3a2f3602ce10c2e032"
-  integrity sha512-2tXEqGxrjvAO6U+CJzDL2Fk2kPHTv1jQsYkSoMeOis2SsYaXRO2COxTdQp99cYvif9JTXaAk9lYGc3VhJt7JPQ==
+postcss@8.4.12:
+  version "8.4.12"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.12.tgz#1e7de78733b28970fa4743f7da6f3763648b1905"
+  integrity sha512-lg6eITwYe9v6Hr5CncVbK70SoioNQIq81nsaG86ev5hAidQvmOeETBqs7jm43K2F5/Ley3ytDtriImV6TpNiSg==
   dependencies:
     nanoid "^3.3.1"
     picocolors "^1.0.0"
@@ -13181,6 +13181,15 @@ postcss@^8.1.7:
     nanoid "^3.1.23"
     source-map-js "^0.6.2"
 
+postcss@^8.4.7:
+  version "8.4.8"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.8.tgz#dad963a76e82c081a0657d3a2f3602ce10c2e032"
+  integrity sha512-2tXEqGxrjvAO6U+CJzDL2Fk2kPHTv1jQsYkSoMeOis2SsYaXRO2COxTdQp99cYvif9JTXaAk9lYGc3VhJt7JPQ==
+  dependencies:
+    nanoid "^3.3.1"
+    picocolors "^1.0.0"
+    source-map-js "^1.0.2"
+
 preact@10.6.6:
   version "10.6.6"
   resolved "https://registry.yarnpkg.com/preact/-/preact-10.6.6.tgz#f1899bc8dab7c0788b858481532cb3b5d764a520"