Remove deprecated macos12 and add macos15 (#153) #615

Job	Run time
msrv	25s
build (ubuntu-latest, stable, false)	2m 26s
build (ubuntu-latest, beta, false)	42s
build (ubuntu-latest, 1.72.0, false)	46s
build (macos-13, stable, false)	4m 19s
build (macos-13, beta, false)	1m 8s
build (macos-13, 1.72.0, false)	1m 20s
build (macos-14, stable, false)	1m 37s
build (macos-14, beta, false)	39s
build (macos-14, 1.72.0, false)	51s
build (macos-15, stable, false)	2m 2s
build (macos-15, beta, false)	38s
build (macos-15, 1.72.0, false)	51s
build (ubuntu-latest, nightly, true)	41s
build (macos-13, nightly, true)	1m 3s
build (macos-14, nightly, true)	43s
build (macos-15, nightly, true)	47s
	20m 58s

Provide feedback