⬆️ Bump cssnano from 6.0.0 to 7.0.6 (#3545)

Bumps [cssnano](https://github.com/cssnano/cssnano) from 6.0.0 to 7.0.6.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/[email protected]@7.0.6)

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

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

Author: dependabot[bot]

@navikt/core/css/package.json

@@ -33,7 +33,7 @@
     "autoprefixer": "^10.4.20",
     "browserslist": "^4.24.2",
     "clean-css": "5.3.3",
-    "cssnano": "6.0.0",
+    "cssnano": "7.0.6",
     "fast-glob": "3.2.11",
     "lightningcss": "^1.28.0",
     "lodash": "^4.17.21",