Update xz to 5.2.5, and switch the download link. (#1296)
Update xz to 5.2.5, and switch the download link. (#1296)

This PR updates xz to 5.2.5, and switch the download link
to use github instead as it is more stable.

Signed-off-by: Yong Tang <765086fe2e0c1f980161f127fec596800f327f62@outlook.com>
tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io