Update the version of the docker image to v4.

[georgeiliadis91]

When creating the docker containers with the documentation currently it installs a container with

"strapi": "3.6.8",
"strapi-admin": "3.6.8",
"strapi-utils": "3.6.8",

The current version is 4.x

[dfang]

why not build images by tags?

[razinj]

I'm facing the same issue -- no official Docker image for Strapi 4, for that I created my own image until there is an official Docker solution, if you are interested you can check my guide here.

[bcdevlucas]

If anyone is looking for an updated project I've created one here:
https://github.com/bluecollardev/strapi-launcher

• Supports Strapi v4 as well as older versions of Strapi (3x, 2x).
• Specify Strapi versions and Node.js versions when building images.
• Updated to use ES modules. As such this library requires Node.js >= 12.
• Uses commander instead of argv for CLI.