Bump immutable in /website in the npm_and_yarn group across 1 directory

Bumps the npm_and_yarn group with 1 update in the /website directory: [immutable](https://github.com/immutable-js/immutable-js).


Updates `immutable` from 4.0.0 to 4.3.8
- [Release notes](https://github.com/immutable-js/immutable-js/releases)
- [Changelog](https://github.com/immutable-js/immutable-js/blob/main/CHANGELOG.md)
- [Commits](immutable-js/immutable-js@v4.0.0...v4.3.8)

---
updated-dependencies:
- dependency-name: immutable
  dependency-version: 4.3.8
  dependency-type: indirect
  dependency-group: npm_and_yarn
...

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

Author: dependabot[bot]