ci: Exclude macos tests below 27.x #42

Job	Run time
test (ubuntu-latest, 26.3, false)	32s
test (ubuntu-latest, 27.2, false)	37s
test (ubuntu-latest, 28.2, false)	43s
test (ubuntu-latest, 29.3, false)	1m 40s
test (macos-latest, 28.2, false)	1m 15s
test (macos-latest, 29.3, false)	1m 30s
test (windows-latest, 26.3, false)	2m 18s
test (windows-latest, 27.2, false)	1m 9s
test (windows-latest, 28.2, false)	55s
test (windows-latest, 29.3, false)	1m 21s
test (ubuntu-latest, snapshot, true)	34s
test (macos-latest, snapshot, true)	1m 13s
test (windows-latest, snapshot, true)	37s
	14m 24s

Provide feedback