Bump postcss from 8.3.6 to 8.4.5

Bumps [postcss](https://github.com/postcss/postcss) from 8.3.6 to 8.4.5.
- [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/8.3.6...8.4.5)

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

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

package.json

@@ -50,7 +50,7 @@
     "lato-font": "^3.0.0",
     "mini-css-extract-plugin": "^2.4.5",
     "node-sass": "^7.0.1",
-    "postcss": "^8.2.7",
+    "postcss": "^8.4.5",
     "postcss-loader": "^6.2.1",
     "sass": "^1.32.8",
     "sass-loader": "^12.4.0",