For consideration - add Dependabot

[case-fastly]

I'm seeing this warning in a project that uses fastly/compute-actions:

Node.js 20 actions are deprecated. The following actions are running on Node.js 20 and may not work as expected: fastly/compute-actions/setup@v12. Actions will be forced to run with Node.js 24 by default starting June 2nd, 2026.

This compute-actions repo uses actions/checkout@v5, which was bumped to v6 back in 2025-November.

I tried adding a .github/dependabot.yml file but ran into Github errors re: forking, etc.

version: 2
updates:
  - package-ecosystem: "github-actions"
    directory: "/"
    schedule:
      interval: "weekly"
    cooldown:
      default-days: 14

Perhaps one of the maintainers could add this.