(docker): add glibc compat to Alpine image

[kevinnls]

the reason

the nokogiri gem depends on glibc

Musl-based systems like Alpine may
not have a glibc-compatible library
installed, leading to problems running
the precompiled native gems.

ref: https://nokogiri.org/tutorials/installing_nokogiri.html#linux-musl-error-loading-shared-library

extensive details at #839

what is affected

1. one more package and its two dependencies are installed via system package manager
2. image size increases by 1MB

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resolves #839