Update supported GitHub Enterprise Server versions #4507

Job	Run time
Ruby analysis (macos-latest, default)	1m 4s
Ruby analysis (ubuntu-latest, linked)	50s
Ruby analysis (macos-latest, linked)	1m 13s
Ruby analysis (ubuntu-latest, default)	51s
Ruby analysis (ubuntu-latest, nightly-latest)	49s
Ruby analysis (macos-latest, nightly-latest)	49s
	5m 36s

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