Add GitHub Copilot instructions for repository #70

Job	Run time
Minimum Supported Rust Version	1m 54s
Clippy	1m 55s
Test (windows-latest, stable)	34m 40s
Test (ubuntu-latest, stable)	15m 24s
Test (macos-latest, stable)	28m 50s
Test (ubuntu-latest, beta)	8m 46s
Format Check	23s
	1h 31m 52s

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