Add initial Copilot instructions #4989

Job	Run time
Go: tracing with legacy workflow (macos-latest, stable-v2.17.6)	3m 14s
Go: tracing with legacy workflow (macos-latest, stable-v2.16.6)	3m 50s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.16.6)	1m 32s
Go: tracing with legacy workflow (macos-latest, stable-v2.19.4)	4m 55s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.17.6)	1m 17s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.19.4)	1m 25s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.18.4)	1m 21s
Go: tracing with legacy workflow (macos-latest, stable-v2.18.4)	4m 12s
Go: tracing with legacy workflow (ubuntu-latest, default)	1m 20s
Go: tracing with legacy workflow (macos-latest, linked)	4m 25s
Go: tracing with legacy workflow (macos-latest, stable-v2.20.7)	2m 56s
Go: tracing with legacy workflow (macos-latest, default)	3m 40s
Go: tracing with legacy workflow (macos-latest, nightly-latest)	3m 35s
Go: tracing with legacy workflow (ubuntu-latest, linked)	1m 17s
Go: tracing with legacy workflow (ubuntu-latest, nightly-latest)	1m 25s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.20.7)	1m 17s
	41m 41s

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