Add GitHub Copilot instructions for repository #72

Job	Run time
Clippy	37s
Minimum Supported Rust Version	38s
Format Check	16s
Test (macos-latest, stable)	14m 18s
Test (ubuntu-latest, stable)	4m 47s
Test (windows-latest, stable)	20m 22s
Test (ubuntu-latest, beta)	4m 53s
	45m 51s

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