chore(deps): Bump actions to latest versions

[Mrtenz]

This bumps actions/checkout from v4 to v5, and actions/setup-node from v4 to v6. The main changes in these new versions are the use of Node 24 to run the actions.

---

Note

Bumps GitHub Actions to latest: actions/checkout v5 and actions/setup-node v6 across workflows and the composite action.

• CI workflows:
  • Bump actions/checkout to v5 across build-lint-test.yml, create-release-pr.yml, main.yml, and publish-release.yml.
  • Bump actions/setup-node to v6 in create-release-pr.yml.
• Composite action (action.yml):
  • Update actions/checkout to v5.
  • Update actions/setup-node (including cache restore step) to v6.

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

[rekmarks]