Bump cssnano from 4.1.11 to 5.0.1

Bumps [cssnano](https://github.com/cssnano/cssnano) from 4.1.11 to 5.0.1.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/v4.1.11...cssnano@5.0.1)

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

package.json

@@ -55,7 +55,7 @@
     "@rollup/plugin-commonjs": "^17.1.0",
     "@rollup/plugin-node-resolve": "^11.2.0",
     "autoprefixer": "^10.2.4",
-    "cssnano": "^4.1.10",
+    "cssnano": "^5.0.1",
     "eslint": "^7.5.0",
     "eslint-config-airbnb-base": "^14.0.0",
     "eslint-plugin-import": "^2.17.3",