Pin test Docker image to Alpine 3.19

[kevinAlbs]

Summary

Pin test Docker image to Alpine 3.19

This is a follow-up to #1088

Background & Motivation

Motivated by this slack thread.

Using alpine:3.19 may be preferable to alpine:3 to prevent unexpected test failures from Alpine image updates. Pinning to a specific version enables intentional upgrade of the image.

Tested on an Ubuntu 22.04 spawn host:

cd extras/docker/alpine3.19
yes | docker system prune -a
make nocachebuild
make test
# Prints `THE alpine3.19 IMAGE WORKS!`

Attempting to test locally on my arm64 macOS resulted in an error building libmongocrypt fixed in MONGOCRYPT-601. MONGOCRYPT-601 is not yet released.

[kkloberdanz]

While I think that there is merit to always test against the latest Alpine image in CI, i.e., using alpine3 as the base image, I don't have a strong opinion either way, so I'm fine with this too.