Build a mult-arch image

[aigarius]

With the new Apple M1 Macs the support for multi-arch images becomes a more interesting/important thing for projects :)

The ruby image that this is using as a base has support for multiple architectures, Jekyll docker release process just needs to use a different base image architecture and then push that to a different architecture (on the same tag).

https://hub.docker.com/layers/ruby/library/ruby/3.0.0-alpine3.13/images/sha256-8a512ce3b5df997576f7bf7b7915b9b7c76a967e04fb95a336af119cb09d7a72?context=explore has the linux/arm64 version and docker/roadmap#142 has some more info on how that works.

[rockstorm101]

Hi all, I've made a temporary fork of this repository to update it to the latest version and build it for ARM platforms. Images are available at rockstorm/jekyll. Hope this helps while @envygeeks comes back.