Draft: feat: remove glibc dependency

Motivation

The dependency complicates multiplatform support (like in helm-install-image!48 (merged)), and there is overhead involved in updating it, so if we don't need it we should remove it. The tests are passing, and our tests are quite comprehensive, so it is unlikely that glibc is still required for any of Auto Deploy's functionality.

Background

The dependency was part of the first prototype of Auto DevOps 😮

It may have been required for any of the following:

• Helm v2
• Tiller
• Kubectl

Discussion

Is this a breaking change? glibc was never a documented feature, so I would argue no, but this could break some advanced usages of auto-deploy-image. In this case, the workaround is to the equivalent of the following commands to the CI/CD job or a derived image:

export GLIBC_VERSION=2.31-r0 # for example
curl -sSL -o /etc/apk/keys/sgerrand.rsa.pub https://alpine-pkgs.sgerrand.com/sgerrand.rsa.pub
curl -sSL -O https://github.com/sgerrand/alpine-pkg-glibc/releases/download/${GLIBC_VERSION}/glibc-${GLIBC_VERSION}.apk
apk add glibc-${GLIBC_VERSION}.apk