Adds a GitHub Actions workflow (`auto-version-bump-scheduler.yml`) that
runs every Tuesday to check for newly published Backstage releases.
The workflow:
- Calls a custom Node.js script (`scripts/ci/trigger-auto-version-bump.js`)
- Checks if a new Backstage minor release was published in the last 7 days
- If true, triggers the `auto-version-bump.yml` workflow
Signed-off-by: Beth Griggs <bethanyngriggs@gmail.com>