Please update the base image

[aetos]

The current base image is ruby:3.1.1-alpine3.15.
In alpine 3.15, apk add bash does not seem to generate /etc/bash/bashrc (it does in 3.16 and later).
Therefore, the common-utils feature cannot be installed when using this image with VSCode DevContainer.

[JV conseil]

Hi 👋

While waiting for @envygeeks to update this repo, I've pushed to Docker Hub an updated version for jekyll/builder image:
https://hub.docker.com/r/jvconseil/jekyll-docker

See also PR #369

Best,
@JV-conseil