Bump clean-css from 5.0.1 to 5.1.2

Bumps [clean-css](https://github.com/jakubpawlowicz/clean-css) from 5.0.1 to 5.1.2.
- [Release notes](https://github.com/jakubpawlowicz/clean-css/releases)
- [Changelog](https://github.com/jakubpawlowicz/clean-css/blob/master/History.md)
- [Commits](https://github.com/jakubpawlowicz/clean-css/compare/v5.0.1...v5.1.2)

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

package-lock.json

@@ -803,9 +803,9 @@
       }
     },
     "clean-css": {
-      "version": "5.0.1",
+      "version": "5.1.2",
-      "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-5.0.1.tgz",
+      "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-5.1.2.tgz",
-      "integrity": "sha512-F1zAGOowUCg8yxT0O4UR+nmbMauf3YwbiUS60CPxpzJU7ulpamGzQomFrJSK4w/HqHtMmQKSHJUNue+dQQYQdg==",
+      "integrity": "sha512-QcaGg9OuMo+0Ds933yLOY+gHPWbxhxqF0HDexmToPf8pczvmvZGYzd+QqWp9/mkucAOKViI+dSFOqoZIvXbeBw==",
       "dev": true,
       "requires": {
         "source-map": "~0.6.0"

package.json

@@ -41,7 +41,7 @@
     "@11ty/eleventy": "^0.11.1",
     "@11ty/eleventy-plugin-syntaxhighlight": "^3.0.6",
     "all-contributors-cli": "^6.19.0",
-    "clean-css": "^5.0.1",
+    "clean-css": "^5.1.2",
     "html-minifier": "^4.0.0",
     "luxon": "^1.25.0",
     "markdown-it": "^12.0.4",