Update supported GitHub Enterprise Server versions #4524

Job	Run time
Diagnostic export (macos-latest, linked)	1m 41s
Diagnostic export (macos-latest, nightly-latest)	1m 42s
Diagnostic export (ubuntu-latest, linked)	1m 7s
Diagnostic export (ubuntu-latest, nightly-latest)	1m 20s
Diagnostic export (windows-latest, linked)	1m 46s
Diagnostic export (windows-latest, nightly-latest)	3m 32s
	11m 8s

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