Bump postcss from 8.4.5 to 8.4.31 in /website

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.5 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@8.4.5...8.4.31)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
...

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

website/yarn.lock

@@ -5667,10 +5667,10 @@ multicast-dns@^6.0.1:
     dns-packet "^1.3.1"
     thunky "^1.0.2"
 
-nanoid@^3.1.30:
-  version "3.2.0"
-  resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-3.2.0.tgz#62667522da6673971cca916a6d3eff3f415ff80c"
-  integrity sha512-fmsZYa9lpn69Ad5eDn7FMcnnSR+8R34W9qJEijxYhTbfOWzr22n1QxCMzXLK+ODyW2973V3Fux959iQoUxzUIA==
+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==
 
 negotiator@0.6.3:
   version "0.6.3"
@@ -6387,13 +6387,13 @@ postcss-zindex@^5.0.1:
   integrity sha512-nwgtJJys+XmmSGoYCcgkf/VczP8Mp/0OfSv3v0+fw0uABY4yxw+eFs0Xp9nAZHIKnS5j+e9ywQ+RD+ONyvl5pA==
 
 postcss@^8.2.15, postcss@^8.3.11, postcss@^8.3.5, postcss@^8.3.7:
-  version "8.4.5"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.5.tgz#bae665764dfd4c6fcc24dc0fdf7e7aa00cc77f95"
-  integrity sha512-jBDboWM8qpaqwkMwItqTQTiFikhs/67OYVvblFFTM7MrZjt6yMKd6r2kgXizEbTTljacm4NldIlZnhbjr84QYg==
+  version "8.4.31"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.31.tgz#92b451050a9f914da6755af352bdc0192508656d"
+  integrity sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==
   dependencies:
-    nanoid "^3.1.30"
+    nanoid "^3.3.6"
     picocolors "^1.0.0"
-    source-map-js "^1.0.1"
+    source-map-js "^1.0.2"
 
 prepend-http@^2.0.0:
   version "2.0.0"
@@ -7387,7 +7387,7 @@ source-list-map@^2.0.0:
   resolved "https://registry.yarnpkg.com/source-list-map/-/source-list-map-2.0.1.tgz#3993bd873bfc48479cca9ea3a547835c7c154b34"
   integrity sha512-qnQ7gVMxGNxsiL4lEuJwe/To8UnK7fAnmbGEEH8RpLouuKbeEm0lhbQVFIrNSuB+G7tVrAlVsZgETT5nljf+Iw==
 
-source-map-js@^1.0.1:
+source-map-js@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/source-map-js/-/source-map-js-1.0.2.tgz#adbc361d9c62df380125e7f161f71c826f1e490c"
   integrity sha512-R0XvVJ9WusLiqTCEiGCmICCMplcCkIwwR11mOSD9CR5u+IXYdiseeEuXCVAjS54zqwkLcPNnmU4OeJ6tUrWhDw==