chore: bump cssnano from 8.0.10 to 9.0.4

Bumps [cssnano](https://github.com/cssnano/cssnano) from 8.0.10 to 9.0.4.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/cssnano@8.0.10...cssnano@9.0.4)

---
updated-dependencies:
- dependency-name: cssnano
  dependency-version: 9.0.4
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

package.json

@@ -4,7 +4,7 @@
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "devDependencies": {
-    "cssnano": "^8.0.0",
+    "cssnano": "^9.0.4",
     "cssnano-preset-advanced": "^8.0.0",
     "gulp": "^5.0.0",
     "gulp-concat": "^2.6.1",