Keep GitHub Actions up to date with GitHub's Dependabot

[cclauss]

From https://github.com/actions/starter-workflows/blob/main/.github/dependabot.yml

Fixes the nine supply chain safety warnings at the bottom right of https://github.com/actions/setup-node/actions/runs/8558803200

Description: Describe your changes.

Related issue: Add link to the related issue.

Check list:

• [ ] Mark if documentation changes are required.
• [ ] Mark if tests were added or updated to cover the changes.