Multi platform docker build

[zigarn]

Fixes #152
Supersedes #182

DockerHub autobuild doesn't support build for ARM (docker/roadmap#109), so switch to GitHub Actions for multi-platform (amd64 & arm64) docker build.

Build amd64 & test for every PR.
Build multi-platform & push only when push on master.

Adaptations:

• sequential build of flavors: this way the with-xxx is built against the latest from same build instead of previous one
• added tests for each flavor (requires absolute paths in Dockerfiles)

@jlandure: I did put my own DOCKERHUB_(USERNAME|TOKEN) as secret, should change it for the technical account dsizenika.

Result: https://github.com/zigarn/alpine-chrome/actions/runs/2327992742 & https://hub.docker.com/repository/docker/zigarn/alpine-chrome-multi-arch/tags

[hgwood]

Thanks a lot!

[zigarn]

@hgwood: need to think to remove auto-build on DockerHub.

[willjosefi]

hey guys!
seems like the PR is merged but I'm not seeing the images from arm64 inside docker hub
plus... seems like gh actions had a failure

[zigarn]

Yes, there are some authentication issues blocking the push.
@jlandure or @hgwood: if you can give me back access to the Zenika's org on DockerHub, I can get the GCR credentials from there (if it's still there) and test what's wrong with it.

[hgwood]

@zigarn Done :)

[zigarn]

Thanks!
Looks like GCR does not accept _json_key_base64 username (https://cloud.google.com/container-registry/docs/advanced-authentication#json-key), unlike GAR (https://cloud.google.com/artifact-registry/docs/docker/authentication#json-key) and despite the doc of docker-login action (https://github.com/marketplace/actions/docker-login#service-account-based-authentication)

[zigarn]

Improved by using a not base64 version of the GCR_JSON_KEY: login is OK: https://github.com/Zenika/alpine-chrome/runs/6858273478?check_suite_focus=true
But push is not...

[zigarn]

@willjosefi: arm64 images are now available!
(https://github.com/zigarn/alpine-chrome/actions/runs/2327992742)