Add Dependabot auto-merge workflow

[Marenz]

Summary

• Add GitHub workflow to automatically approve and merge Dependabot PRs
• Uses merge method for clean commit history

[Copilot]

Pull Request Overview

This PR adds a GitHub workflow to automatically approve and merge Dependabot pull requests, enabling automated dependency updates with minimal manual intervention.

Key changes:

• Introduces a new GitHub Actions workflow that triggers on pull requests
• Implements automatic approval and merging specifically for Dependabot-created PRs
• Configures the merge method to use 'merge' for maintaining clean commit history

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[Copilot]

The workflow triggers on all pull request events without specifying event types. This could cause unnecessary workflow runs. Consider adding specific event types like 'opened' and 'synchronize', or use 'pull_request_target' with appropriate security considerations for auto-merge scenarios.

Suggested change

	types: [opened, synchronize]

[Marenz]

This is ready but needs repo owner approval. Also probably will not work if that is enabled as the merge bot needs approval access