Bump clean-css from 5.3.0 to 5.3.1

Bumps [clean-css](https://github.com/clean-css/clean-css) from 5.3.0 to 5.3.1.
- [Release notes](https://github.com/clean-css/clean-css/releases)
- [Changelog](https://github.com/clean-css/clean-css/blob/master/History.md)
- [Commits](clean-css/clean-css@v5.3.0...v5.3.1)

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

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

package.json

@@ -27,7 +27,7 @@
     "@11ty/eleventy-img": "2.0.1",
     "bootstrap": "5.2.0",
     "browser-sync": "^2.27.10",
-    "clean-css": "^5.3.0",
+    "clean-css": "^5.3.1",
     "gulp": "^4.0.2",
     "gulp-clean": "^0.4.0",
     "gulp-clean-css": "^4.2.0",