GitHub Actions: audit all actions for Node 16 deprecation ahead of June 2026 deadline

[Computer-Tsu]

Description

GitHub is deprecating Node.js 16-based Actions runtimes. Workflows that use actions still running on Node 16 will begin generating warnings and will stop working after the deprecation deadline (~June 2026). All workflow files should be audited and action versions pinned to Node 20-compatible releases.

Dependabot has already opened PR #9 to bump actions/setup-dotnet from v4 to v5, which is the most visible instance — but all actions across all workflow files should be reviewed as part of a single coordinated pass.

Workflows to Audit

• .github/workflows/build.yml
• .github/workflows/codeql.yml
• .github/workflows/dependency-review.yml
• .github/workflows/format-check.yml
• .github/workflows/json-validate.yml
• .github/workflows/markdown-lint.yml

Actions to Verify

Action	Current	Check
actions/checkout	—	Confirm v4+
actions/setup-dotnet	v4 → v5 via PR #9	Covered by #9
actions/upload-artifact	—	Confirm v4+
actions/download-artifact	—	Confirm v4+
github/codeql-action	—	Confirm v3+
actions/dependency-review-action	—	Confirm current
DavidAnson/markdownlint-cli2-action	—	Confirm current

Resolution

• Merge PR chore(actions): bump actions/setup-dotnet from 4 to 5 #9 to address setup-dotnet
• Update any remaining actions to their latest Node 20-compatible version
• Consider adding Dependabot config to monitor all action versions going forward (already partially in place via .github/dependabot.yml)