Version the shell files outside of init.rs

zerobrew is serving as a bad citizen by insisting on setting these widely used environment variables.

https://github.com/lucasgelfond/zerobrew/blob/8d9af905c5508972066ac4dc03f65336bb44d5f0/zb_cli/src/init.rs#L301-L347

I don't have zerobrew-managed ca-certificates installed, don't want, and don't need.

A considerate developer or agent, would create a ZEROBREW_SSL_CERT_FILE or ZEROBREW_SSL_CERT_DIR env vars to use

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I re-attempted to install from tap, which left me with v0.1.1, already filed #386 here and there https://github.com/lucasgelfond/homebrew-zerobrew/issues/1.