chore: let Dependabot keep GitHub Actions up to date

[erwan-joly]

Replaces the saadmk11/github-actions-version-updater approach with Dependabot's native github-actions ecosystem.

Dependabot now does this natively: it updates action versions, maintains SHA pins and their trailing version comments (which matters since every action in this estate is pinned to a SHA), and — unlike the action — it closes its own PRs when they stop being relevant, so stale update PRs do not accumulate.

It also needs no token: the action required a PAT with workflow scope to push workflow changes, which was one more long-lived credential to hold.

Matches the ecosystem block already present in NosCoreIO/NosCore.

Summary by CodeRabbit

• Chores
  • Added weekly automated update checks for GitHub Actions.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Advanced

Run ID: aa9f276c-9011-4c8a-9c23-1b5ec91841bf

📥 Commits

Reviewing files that changed from the base of the PR and between 941bf2f and 7730a74.

📒 Files selected for processing (1)

• .github/dependabot.yml

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

---

Walkthrough

The pull request adds a Dependabot configuration for weekly GitHub Actions updates in the repository root.

Changes

Dependabot Updates

Layer / File(s)	Summary
GitHub Actions update schedule .github/dependabot.yml	Defines weekly Dependabot updates for GitHub Actions targeting the repository root.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~2 minutes

Change: Other

Merge Risk: ⚪ Minimal · up to 7730a

This PR only enables weekly Dependabot updates for GitHub Actions and is ready to merge.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: adding Dependabot to keep GitHub Actions up to date.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/dependabot-github-actions

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}