The description of the Docker images in README

[xlionjuan]

@paspo @rustdesk

I think the description of the Docker images in README is a little messy, we've already bind multi arch images to latest tag, it is unnecessary to guile user to find and type its architecture to the end of the tag, eg. latest-amd64, Docker or Podman itself will choose right architecture, only the latest and major (eg. 1) tag is needed, and it is also multi arch tag.

What both of you think?

[xlionjuan]

Draft PR here: #479