Bump js-yaml and cssnano

Removes [js-yaml](https://github.com/nodeca/js-yaml). It's no longer used after updating ancestor dependency [cssnano](https://github.com/cssnano/cssnano). These dependencies need to be updated together.


Removes `js-yaml`

Updates `cssnano` from 4.1.10 to 7.1.2
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/v4.1.10...cssnano@7.1.2)

---
updated-dependencies:
- dependency-name: js-yaml
  dependency-version: 
  dependency-type: indirect
- dependency-name: cssnano
  dependency-version: 7.1.2
  dependency-type: direct:development
...

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

package.json

@@ -22,7 +22,7 @@
     "@types/node": "^16.11.1",
     "@web/rollup-plugin-import-meta-assets": "^1.0.6",
     "comlink": "^4.3.0",
-    "cssnano": "^4.1.10",
+    "cssnano": "^7.1.2",
     "dedent": "^0.7.0",
     "del": "^5.1.0",
     "file-drop-element": "^1.0.1",