Updated xz to 5.6.4 #527

Job	Run time
macOS 10.10 x86_64	22m 18s
macOS 10.13 x86_64	23m 0s
macOS 10.15 x86_64	17m 23s
macOS arm64	20m 50s
manylinux2014 and musllinux x86_64	37m 29s
manylinux_2_28 x86_64	19m 9s
manylinux2014 and musllinux aarch64	33m 59s
manylinux_2_28 aarch64	18m 42s
sdist	22s
Windows x86	20m 8s
Windows AMD64	30m 51s
Windows ARM64	13m 18s
Upload wheels to scientific-python-nightly-wheels	0s
Upload release to PyPI	0s
	4h 17m 29s

Provide feedback