Merge https://github.com/google/adk-python/pull/3932
## Summary
Upgrade GitHub Actions to their latest versions to ensure compatibility with Node 24, as Node 20 will reach end-of-life in April 2026.
## Changes
| Action | Old Version(s) | New Version | Release | Files |
|--------|---------------|-------------|---------|-------|
| `actions/checkout` | [`v5`](https://github.com/actions/checkout/releases/tag/v5) | [`v6`](https://github.com/actions/checkout/releases/tag/v6) | [Release](https://github.com/actions/checkout/releases/tag/v6) | analyze-releases-for-adk-docs-updates.yml, check-file-contents.yml, discussion_answering.yml, isort.yml, pr-triage.yml, pyink.yml, python-unit-tests.yml, stale-bot.yml, triage.yml, upload-adk-docs-to-vertex-ai-search.yml |
## Context
Per [GitHub's announcement](https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/), Node 20 is being deprecated and runners will begin using Node 24 by default starting March 4th, 2026.
### Why this matters
- **Node 20 EOL**: April 2026
- **Node 24 default**: March 4th, 2026
- **Action**: Update to latest action versions that support Node 24
### Security Note
Actions that were previously pinned to commit SHAs remain pinned to SHAs (updated to the latest release SHA) to maintain the security benefits of immutable references.
### Testing
These changes only affect CI/CD workflow configurations and should not impact application functionality. The workflows should be tested by running them on a branch before merging.
Co-authored-by: Xiang (Sean) Zhou <seanzhougoogle@google.com>
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/3932 from salmanmkc:upgrade-github-actions-node24 0ffbb0b7b5f63d27583f8c24781f2d3ca92c0c23
PiperOrigin-RevId: 845813166
Liang WuandCopybara-Service
George WealeandCopybara-Service
Salman ChishtiandCopybara-Service
Giorgio BoaandCopybara-Service