Update supported GitHub Enterprise Server versions #5104

Job	Run time
Ruby analysis (ubuntu-latest, default)	48s
Ruby analysis (macos-latest, linked)	1m 47s
Ruby analysis (ubuntu-latest, linked)	50s
Ruby analysis (macos-latest, default)	3m 52s
Ruby analysis (ubuntu-latest, nightly-latest)	1m 9s
Ruby analysis (macos-latest, nightly-latest)	1m 53s
	10m 19s

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