Enable Dependabot for dependency and GitHub Actions updates

[Lang-Akshay]

Summary

Set up Dependabot in this repository so dependency and GitHub Actions updates are created automatically via pull requests.

Why

• Improve security posture by receiving timely dependency updates.
• Reduce manual maintenance burden for Rust and Python plugin packages.
• Keep CI workflows up to date.

Scope

Add .github/dependabot.yml configured for:

• github-actions (repository workflows)
• cargo (root and plugin/crate manifests)
• pip (Python plugin package dependencies)

Proposed Configuration

• Run schedule: weekly
• Group minor/patch updates where practical to reduce PR noise
• Use sensible PR limits (e.g., max 5 open PRs per ecosystem)
• Add labels such as dependencies and security
• Assign reviewers/team if repository policy requires it

Acceptance Criteria

• A valid .github/dependabot.yml is present on main.
• Dependabot is enabled for github-actions, cargo, and pip.
• At least one Dependabot PR is opened successfully after merge.
• CI passes for Dependabot-generated PRs, or documented follow-up issues are created.

Notes

Repository is a monorepo with multiple independent plugin packages (Rust and Python), so directory coverage in dependabot.yml should include all relevant manifests.

[lucarlig]

this can be done through GitHub repo setting as well from any admin