DEVEX-1090: Upgrade deprecated GitHub Actions to Node.js 24 compatible versions

[pdodgen-revparts]

Summary

• Upgrade actions/checkout to v6 (from v2/v3/v4)
• Upgrade actions/cache to v5 (from v2/v3/v4)
• Upgrade nick-invision/retry to nick-fields/retry@v4 (author renamed account + Node.js 24 support)

These upgrades resolve the Node.js 20 deprecation warnings. GitHub Actions will force Node.js 24 starting June 2nd, 2026.

All upgrades are backward compatible with no breaking changes to workflow behavior.

Test plan

• Verify CI workflows pass on this branch
• Confirm no workflow behavior changes

Ticket: DEVEX-1090

[cursor]

PR Summary

Low Risk
Low risk version bumps across CI workflows, but they touch many pipelines so any upstream action behavior change could cause unexpected CI/deploy failures.

Overview
Updates GitHub Actions workflow dependencies to newer, Node.js 24-compatible versions.

Across the shared workflows, bumps actions/checkout to v6, actions/cache to v5, and replaces nick-invision/retry with nick-fields/retry@v4 where used, without changing the surrounding workflow logic.

^{Written by Cursor Bugbot for commit 756f613. This will update automatically on new commits. Configure here.}