Bump postcss from 8.3.5 to 8.3.6 in /build/javascript (#1240)

Bumps [postcss](https://github.com/postcss/postcss) from 8.3.5 to 8.3.6.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.3.5...8.3.6)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

build/javascript/package-lock.json

@@ -1443,9 +1443,9 @@
       }
     },
     "postcss": {
-      "version": "8.3.5",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.3.5.tgz",
-      "integrity": "sha512-NxTuJocUhYGsMiMFHDUkmjSKT3EdH4/WbGF6GCi1NDGk+vbcUTun4fpbOqaPtD8IIsztA2ilZm2DhYCuyN58gA==",
+      "version": "8.3.6",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.3.6.tgz",
+      "integrity": "sha512-wG1cc/JhRgdqB6WHEuyLTedf3KIRuD0hG6ldkFEZNCjRxiC+3i6kkWUUbiJQayP28iwG35cEmAbe98585BYV0A==",
       "dev": true,
       "requires": {
         "colorette": "^1.2.2",

build/javascript/package.json

@@ -16,7 +16,7 @@
   },
   "devDependencies": {
     "cssnano": "^5.0.7",
-    "postcss": "^8.3.5",
+    "postcss": "^8.3.6",
     "postcss-cli": "^8.3.1"
   },
   "snowpack": {