Upgrade actions/checkout to v4 (#4122)
This eliminates reported by Action runs:
> **Spell Check with Typos**
> Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v2. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.
