ci: build multi arch images with buildx

[rr-nick-tan]

What this PR does / why we need it:

build multi arch images with buildx
fixes #335

Which issue this PR fixes

(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)

• fixes #

Special notes:

Checklist chart

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• Chart Version bumped
• Variables are documented in the README.md

[rr-nick-tan]

@jtblin , pls review

when you create the git tag, it triggers the image build and publish to Docerhub
it works in my fork https://github.com/rr-nick-tan/kube2iam/runs/5441826765?check_suite_focus=true
to make the release work, you need to provide the github secrets DOCKERHUB_USERNAME and DOCKERHUB_TOKEN

[linki]

@rr-nick-tan I think you can remove all your changes in this file. When the image is built by buildx it should automatically pick up the correct variant for the target platform. Maybe you can give it a try?

[linki]

You could try using the build-and-push action to have it deal with all the buildx stuff. Here's an example that worked for me: https://github.com/linki/chaoskube/blob/1d44a96fd6f71d75dbcbf96f5a5a4b198913bcf1/.github/workflows/container-image.yml#L52-L59

[tburko]

@linki can this be done as a separate PR? would appreciate if 0.11.0 multi-arch was published

[linki]

@tburko Yes, sure 👍