chore(deps-dev): bump cssnano from 5.1.15 to 6.0.0 (#8529)

Bumps [cssnano](https://github.com/cssnano/cssnano) from 5.1.15 to 6.0.0.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/cssnano@5.1.15...cssnano@6.0.0)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -129,7 +129,7 @@
     "cors": "^2.8.5",
     "cross-env": "=7.0.3",
     "css-loader": "=6.7.1",
-    "cssnano": "=5.1.15",
+    "cssnano": "=6.0.0",
     "cypress": "=9.5.1",
     "dedent": "^0.7.0",
     "deepmerge": "^4.0.0",