Downgrade zlib on Linux instead of auditwheel

[radarhere]

#225 downgraded auditwheel on Linux because auditwheel started raising an error when we tried to include zlib 1.2.11. The error was because auditwheel requires manylinux_2_27 for zlib 1.2.9, and we are currently distributing manylinux_2_17 wheels.

The zlib requirements were added to auditwheel in pypa/auditwheel#334, which used information from mayeut/pep600_compliance#88.

In other words, I've concluded that by ignoring this error, we're violating PEP 600. python.org gives a similar example to this in the documentation - https://www.python.org/dev/peps/pep-0600/

Example: if a wheel is tagged as manylinux_2_17_x86_64, but it uses symbols that were only added in glibc 2.18, then that wheel won't work on systems with glibc 2.17. Therefore, we can conclude that this wheel is in violation of this specification.

So this PR suggests using the latest version of auditwheel again, to restore our PEP 600 compliance, and downgrading zlib to 1.2.8 on Linux instead.

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Why can't we upgrade to manylinux_2_27? Primarily, to continue offering support for CentOS 7 (listed as manylinux_2_17), EOL on June 30, 2024, and Amazon Linux 2 (listed as manylinux_2_26), EOL on June 30, 2023.

pypa/manylinux#1012 (comment)

Project who wish to support centos7/rhubi7 will need manylinux2_17 (manylinux2014) until 2024.

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But wait, you say, could we do both? Could we generate manylinux_2_17 and manylinux_2_27 wheels, so that CentOS 7 and Amazon Linux 2 users could install the older wheels, and everyone else could continue to use zlib 1.2.11?

Well, multibuild will only let us specify manylinux_2_24 at best, which still doesn't support zlib 1.2.9. This limitation in multibuild is to be expected though, since manylinux doesn't have any higher Docker images yet.

[hugovk]

Thanks!

[radarhere]

manylinux have now released images for _2_28, so I have created #301 to add those wheels

[radarhere]

Amazon Linux 2 (listed as manylinux_2_26), EOL on June 30, 2023.

Update: https://aws.amazon.com/amazon-linux-2/faqs/ currently states

Amazon Linux 2 end of support date (End of Life, or EOL) has been extended by two years from 2023-06-30 to 2025-06-30 to provide customers with ample time to migrate to the next version.