build(deps): bump postcss from 8.4.17 to 8.4.18 (#5508)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.17 to 8.4.18.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.17...8.4.18)

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

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Matt Driscoll <mdriscoll@esri.com>
Co-authored-by: Ben Elan <belan@esri.com>

package.json

@@ -132,7 +132,7 @@
     "jest-axe": "6.0.0",
     "jest-cli": "27.4.5",
     "lint-staged": "13.0.3",
-    "postcss": "8.4.17",
+    "postcss": "8.4.18",
     "prettier": "2.7.1",
     "puppeteer": "10.0.0",
     "quicktype-core": "6.1.0",