Keep GitHub Actions up to date with GitHub's Dependabot

Keep GitHub Actions up to date with GitHub's Dependabot dependabot.yml

* [Keeping your actions up to date with Dependabot](https://docs.github.com/en/code-security/dependabot/working-with-dependabot/keeping-your-actions-up-to-date-with-dependabot)
* [Configuration options for the dependabot.yml file - package-ecosystem](https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#package-ecosystem)

.github/dependabot.yml

@@ -4,3 +4,11 @@ updates:
  directory: "/"
  schedule:
  interval: "monthly"
+ - package-ecosystem: "github-actions"
+ directory: "/"
+ groups:
+ github-actions:
+ patterns:
+ - "*" # Group all Actions updates into a single larger pull request
+ schedule:
+ interval: "weekly"