build(deps): bump postcss from 8.4.8 to 8.4.12 (#4511)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.8 to 8.4.12.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.8...8.4.12)

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

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

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

Author: dependabot[bot]

package-lock.json

@@ -52,7 +52,7 @@
     "ncp": "^2.0.0",
     "node-version-data": "^1.1.0",
     "npm-run-all": "^4.1.5",
-    "postcss": "^8.4.8",
+    "postcss": "^8.4.12",
     "sass": "^1.49.9",
     "semver": "^7.3.5",
     "strftime": "^0.10.1"