ci: Bump Emacs 29.x to 3 #33

Job	Run time
test (ubuntu-latest, 26.3, false)	32s
test (ubuntu-latest, 27.2, false)	29s
test (ubuntu-latest, 28.2, false)	35s
test (ubuntu-latest, 29.3, false)	30s
test (macos-latest, 26.3, false)	1m 48s
test (macos-latest, 27.2, false)	1m 34s
test (macos-latest, 28.2, false)	1m 53s
test (macos-latest, 29.3, false)	1m 51s
test (windows-latest, 26.3, false)	1m 59s
test (windows-latest, 27.2, false)	1m 5s
test (windows-latest, 28.2, false)	41s
test (windows-latest, 29.3, false)	50s
test (ubuntu-latest, snapshot, true)	26s
test (macos-latest, snapshot, true)	2m 9s
test (windows-latest, snapshot, true)	33s
	16m 55s

Provide feedback