update qemu to 8.1.5 #558

Job	Run time
prepare (mainline)	7m 42s
prepare (buildkit)	7m 32s
prepare (desktop)	7m 45s
validate (./hack/lint)	27s
e2e (mainline, pip-youtube-dl, linux/arm/v7)	1m 13s
validate (./hack/validate-vendor)	16s
e2e (mainline, webpack, linux/arm/v7)	1m 47s
test (mainline)	2m 42s
validate (./hack/install-and-test)	36s
e2e (desktop, pip-youtube-dl, linux/arm/v7)	1m 10s
test (buildkit)	30s
e2e (desktop, webpack, linux/arm/v7)	1m 46s
test (desktop)	10s
e2e (mainline, ejabberd, linux/arm64)	13m 34s
e2e (desktop, tini, linux/arm64, true)	35s
build (mainline)	30m 55s
build (buildkit)	29m 56s
build (desktop)	31m 17s
	2h 19m 53s

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