Add github-actions dependency grouping to dependabot configuration

[Copilot]

Pull Request

Description

Syncs the dependabot configuration with the TemplateDotNetLibrary template by adding a groups block to the github-actions ecosystem entry. This groups all GitHub Actions updates into a single weekly PR, consistent with how NuGet dependencies are already handled.

  - package-ecosystem: "github-actions"
    ...
    groups:
      github-actions-dependencies:
        patterns:
          - "*"

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code quality improvement

Related Issues

Closes #

Pre-Submission Checklist

Before submitting this pull request, ensure you have completed the following:

Build and Test

• Code builds successfully: dotnet build --configuration Release
• All unit tests pass: dotnet test --configuration Release
• Code produces zero warnings

Code Quality

• Code formatting is correct: dotnet format --verify-no-changes
• New code has appropriate XML documentation comments
• Static analyzer warnings have been addressed

Quality Checks

Please run the following checks before submitting:

• Spell checker passes: cspell "**/*.{md,cs}"
• Markdown linter passes: markdownlint "**/*.md"
• YAML linter passes: yamllint .

Testing

• Added unit tests for new functionality
• Updated existing tests if behavior changed
• All tests follow the AAA (Arrange, Act, Assert) pattern
• Test coverage is maintained or improved

Documentation

• Updated README.md (if applicable)
• Added code examples for new features (if applicable)
• Updated requirements.yaml (if applicable)
• Updated XML documentation comments for changed APIs

Additional Notes

Configuration-only change. No code, tests, or documentation affected.

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