Update docs-deploy workflow to latest action versions

[Copilot]

The docs-deploy workflow was using deprecated GitHub Actions versions and an EOL Node.js runtime.

Changes

• Actions updated to v4: actions/checkout@v2.3.5 → v4, actions/setup-node@v2 → v4, crazy-max/ghaction-github-pages@v2 → v4
• Node.js runtime: 14 (EOL April 2023) → 20 (current LTS)
• Security: Added explicit permissions: contents: write to limit GITHUB_TOKEN scope
• Tracking: Removed .github/.gitignore that was preventing workflow versioning

jobs:
  deploy:
    permissions:
      contents: write
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: "20"
      - uses: crazy-max/ghaction-github-pages@v4

Original prompt

update docs-deploy pipeline yaml with latest action versions and fix deprecated stuff

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[Pushpavel]

@copilot Make the changes on docs branch, not in main branch

[Copilot]

@copilot Make the changes on docs branch, not in main branch

I understand you'd like this PR to target the docs branch instead of main. However, I don't have the ability to change the base branch of an existing PR.

You can change the base branch yourself by:

1. Going to the PR page on GitHub
2. Clicking "Edit" next to the title
3. Clicking "Edit" on the base branch dropdown
4. Selecting docs as the new base branch

Alternatively, if you'd prefer, I can revert all changes and you can close this PR, then create a new issue requesting the same changes but specifying the docs branch as the target.