chore: Add Dependabot version-update cooldown

[ld-repository-standards]

This pull request was auto generated by the LaunchDarkly Github Standards automation platform.

• Ensure every entry under updates in .github/dependabot.yml declares a cooldown of at least 7 days (default-days).
• Add entries for detected package ecosystems that were not yet tracked by Dependabot.

Cooldown applies only to version updates; security updates bypass it, so critical CVE fixes are never delayed.

Ref: SEC-8058.

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Note

Low Risk
CI-only Dependabot configuration with no changes to application, auth, or runtime behavior.

Overview
Introduces .github/dependabot.yml to automate dependency updates with a 7-day cooldown on version bumps (default-days: 7) for each tracked ecosystem.

Docker is enabled for the example apps under examples/hello-debian, hello-haproxy, and hello-nginx on a weekly schedule. GitHub Actions at the repo root is also on weekly updates with the same cooldown. Cooldown applies to routine version PRs only; security updates are not delayed by this setting.

^{Reviewed by Cursor Bugbot for commit f69e895. Bugbot is set up for automated code reviews on this repo. Configure here.}

[pkaeding]

Closing -- The automation has been updated to not enable version-updates if it isn't already enabled.

via LD Research 🤖