Support container images for the ARM64 architecture

[stormcat24]

What would you like to be added:

Build and release the container images for the ARM64 architecture.

Why is this needed:

I want to run PipeCD on ARM64-based Graviton2 to reduce AWS running costs. Many AWS users will welcome the release of container images for the ARM64 architecture.

What do you think?

[hungran]

I'd like to work on this issue
correct me if i'm wrong
I was tried from my local environment which using docker buildx to build linux/arm64 for only Piped and PipeCD image, and quick setup with helm pipecd and piped seem ok
not sure with piped-okd and launcher

do you have any concern on that or with current situation, I believe just have platform linux/arm64 in github action docker build is enough?
maybe here?
https://github.com/hungran/pipecd/blob/master/.github/workflows/publish_image_chart.yaml#L77-L78

[hungran]

I believed this issue was solved by this
#4552

[kentakozuka]

Solved by #4552.
Feel free to reopen if this is not yet fixed 👍
@hungran Big thanks!