Bump cssnano from 5.1.14 to 6.0.1

Bumps [cssnano](https://github.com/cssnano/cssnano) from 5.1.14 to 6.0.1.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/[email protected]@6.0.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package.json

@@ -9,7 +9,7 @@
   "devDependencies": {
     "@fullhuman/postcss-purgecss": "5.0.0",
     "autoprefixer": "^10.4.13",
-    "cssnano": "^5.1.14",
+    "cssnano": "^6.0.1",
     "cssnano-preset-advanced": "^5.3.9",
     "nodemon": "^2.0.19",
     "pdf-lib": "^1.17.1",