docker image: use client-libs-test

[mgravell]

This is an image specifically intended for client library development, and in particular: offers preview builds ahead of the main redis image. In this case: 8.4-rc1 (which identifies as redis_version:8.3.224).

Caveat: docker setup is not my strong suit... this may be a little iterative.

[mgravell]

Might not be "taking" on Windows...

Checking redis-server version with port 26380
redis_version:8.2.2
Checking redis-server version with port 26381
redis_version:8.2.2

hey @NickCraver - any idea why ^^^ ? This is from "Run redis-server" on the Windows Server 2022 run.

Edit: ah, I see; the Windows build just uses apt-get install -y redis, rather than docker, from here. That's fine, I guess. I'll refer mostly to the Ubuntu image for the docker usage.