Update zlib to v1.3

Clemens Lange requested to merge zlib_1_3 into master

See http://www.zlib.net/ Unfortunately, they always yank older versions...

We could also just switch to "latest" by using http://www.zlib.net/current/zlib.tar.gz instead.

BTW @mccauley would you mind taking over ownership of the pipelines at https://gitlab.cern.ch/cms-cloud/cmssw-docker/-/pipeline_schedules such that you get notified if there's an issue?

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