Bump cssnano from 6.0.5 to 6.1.1

Bumps [cssnano](https://github.com/cssnano/cssnano) from 6.0.5 to 6.1.1.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/cssnano@6.0.5...cssnano@6.1.1)

---
updated-dependencies:
- dependency-name: cssnano
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -224,7 +224,7 @@
     "css-loader": "6.10.0",
     "css-selector-tokenizer": "0.8.0",
     "cssesc": "3.0.0",
-    "cssnano": "6.0.5",
+    "cssnano": "6.1.1",
     "csso": "5.0.5",
     "cssom": "0.5.0",
     "cssstyle": "4.0.1",