Bump postcss from 8.4.21 to 8.4.31

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: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

yarn.lock

@@ -2718,9 +2718,9 @@ multicast-dns@^7.2.5:
     dns-packet "^5.2.2"
     thunky "^1.0.2"
 
-nanoid@^3.3.4:
+nanoid@^3.3.6:
   version "3.3.6"
-  resolved "https://registry.npmjs.org/nanoid/-/nanoid-3.3.6.tgz"
+  resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-3.3.6.tgz#443380c856d6e9f9824267d960b4236ad583ea4c"
 
 [email protected]:
   version "0.6.3"
@@ -3124,10 +3124,10 @@ postcss-value-parser@^4.1.0, postcss-value-parser@^4.2.0:
   resolved "https://registry.npmjs.org/postcss-value-parser/-/postcss-value-parser-4.2.0.tgz"
 
 postcss@^8.2.14, postcss@^8.4.17, postcss@^8.4.19:
-  version "8.4.21"
-  resolved "https://registry.npmjs.org/postcss/-/postcss-8.4.21.tgz"
+  version "8.4.31"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.31.tgz#92b451050a9f914da6755af352bdc0192508656d"
   dependencies:
-    nanoid "^3.3.4"
+    nanoid "^3.3.6"
     picocolors "^1.0.0"
     source-map-js "^1.0.2"