Bump postcss from 8.3.5 to 8.4.31 in /website (#564)

Bumps [postcss](https://github.com/postcss/postcss) from 8.3.5 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@8.3.5...8.4.31)

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

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

website/package-lock.json

@@ -7291,11 +7291,6 @@
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       "optional": true
     },
-    "nanoid": {
-      "version": "3.2.0",
-      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.2.0.tgz",
-      "integrity": "sha512-fmsZYa9lpn69Ad5eDn7FMcnnSR+8R34W9qJEijxYhTbfOWzr22n1QxCMzXLK+ODyW2973V3Fux959iQoUxzUIA=="
-    },
     "nanomatch": {
       "version": "1.2.13",
       "resolved": "https://registry.npmjs.org/nanomatch/-/nanomatch-1.2.13.tgz",
@@ -7765,6 +7760,11 @@
       "resolved": "https://registry.npmjs.org/path-type/-/path-type-4.0.0.tgz",
       "integrity": "sha512-gDKb8aZMDeD/tZWs9P6+q0J9Mwkdl6xMV8TjnGP3qJVJ06bdMgkbBlLU8IdfOsIsFz2BW1rNVT3XuNEl8zPAvw=="
     },
+    "picocolors": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.0.0.tgz",
+      "integrity": "sha512-1fygroTLlHu66zi26VoTDv8yRgm0Fccecssto+MhsZ0D/DGW2sm8E8AjW7NU5VVTRt5GxbeZ5qBuJr+HyLYkjQ=="
+    },
     "picomatch": {
       "version": "2.3.0",
       "resolved": "https://registry.npmjs.org/picomatch/-/picomatch-2.3.0.tgz",
@@ -7870,13 +7870,25 @@
       "integrity": "sha1-AerA/jta9xoqbAL+q7jB/vfgDqs="
     },
     "postcss": {
-      "version": "8.3.5",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.3.5.tgz",
-      "integrity": "sha512-NxTuJocUhYGsMiMFHDUkmjSKT3EdH4/WbGF6GCi1NDGk+vbcUTun4fpbOqaPtD8IIsztA2ilZm2DhYCuyN58gA==",
+      "version": "8.4.31",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.4.31.tgz",
+      "integrity": "sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==",
       "requires": {
-        "colorette": "^1.2.2",
-        "nanoid": "^3.1.23",
-        "source-map-js": "^0.6.2"
+        "nanoid": "^3.3.6",
+        "picocolors": "^1.0.0",
+        "source-map-js": "^1.0.2"
+      },
+      "dependencies": {
+        "nanoid": {
+          "version": "3.3.6",
+          "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.6.tgz",
+          "integrity": "sha512-BGcqMMJuToF7i1rt+2PWSNVnWIkGCU78jBG3RxO/bZlnZPK2Cmi2QaffxGO/2RvWi9sL+FAiRiXMgsyxQ1DIDA=="
+        },
+        "source-map-js": {
+          "version": "1.0.2",
+          "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.0.2.tgz",
+          "integrity": "sha512-R0XvVJ9WusLiqTCEiGCmICCMplcCkIwwR11mOSD9CR5u+IXYdiseeEuXCVAjS54zqwkLcPNnmU4OeJ6tUrWhDw=="
+        }
       }
     },
     "postcss-calc": {
@@ -9677,11 +9689,6 @@
       "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.5.7.tgz",
       "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w="
     },
-    "source-map-js": {
-      "version": "0.6.2",
-      "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-0.6.2.tgz",
-      "integrity": "sha512-/3GptzWzu0+0MBQFrDKzw/DvvMTUORvgY6k6jd/VS6iCR4RDTKWH6v6WPwQoUO8667uQEf9Oe38DxAYWY5F/Ug=="
-    },
     "source-map-resolve": {
       "version": "0.5.3",
       "resolved": "https://registry.npmjs.org/source-map-resolve/-/source-map-resolve-0.5.3.tgz",