Add Dependabot configuration for automated dependency updates

[mr-raj12]

The problem

The repository currently does not include a .github/dependabot.yml configuration file. As a result, GitHub Actions versions and Python dependencies can become outdated silently, requiring manual discovery and maintenance.

For example, actions/checkout is currently pinned to v3, which runs on Node.js 16 (now EOL). This issue would have been automatically detected and addressed if Dependabot were enabled.

---

Requested Solution

Add a .github/dependabot.yml file with the following configurations:

• github-actions
  Enable weekly automatic updates for GitHub Actions used in workflow files.

• pip
  Enable weekly automatic updates for Python dependencies defined in pyproject.toml.

---

Alternatives

Renovate Bot is a possible alternative; however, Dependabot is natively integrated with GitHub and requires no additional setup. Additionally, pre-commit.ci already manages pre-commit hook updates, so Dependabot would cover the remaining dependency categories.

---

Additional context

New file to be added:

• .github/dependabot.yml