Add approve-dependabot-pr workflow using reusable workflow

[rajbos]

This PR adds the missing approve-dependabot-pr.yml workflow to align with other repositories in the devops-actions organization.

Changes

• ✅ Added approve-dependabot-pr.yml using the reusable workflow from .github repo
  • Automatically approves and enables auto-merge for minor and patch Dependabot updates
  • Uses the same pattern as all other repos in the organization

Benefits

• Consistency across all devops-actions repositories
• Easier maintenance - updates to the workflow happen in one place (.github repo)
• Automates Dependabot PR approval, reducing manual review burden for dependency updates
• Follows organizational standards

Testing

• This workflow is already tested and working in other repositories in the organization
• Uses the centrally maintained reusable workflow from devops-actions/.github

[github-actions]

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