Add support for building docker image for linux/arm64

[kfiven]

Description

This PR add support to build docker image for linux/arm64 platform. Currently we only have it for linux/amd64.

Fixes #489

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

Preview: https://6291e81eb669225c2ec924b6--pr-cinny.netlify.app
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[kfiven]

Btw build times has gone 10x, and I don't know why.

[GoliathLabs]

@kfiven, since we use qemu to build arm64 (a non-native platform for the gh-action VMs), it takes much longer. It would be recommended to build arm64 images only when a new tag is pushed (as possibly multiple build processes can run at the same time and overwrite the other one, depending on which one finishes first)

[anthr76]

I would like to have this merged as I have a multi-arch Kubernetes cluster I would like to deploy this on.

[ivanjx]

why not just build with whatever system you are running on then just use the arm64 of nginx for example?

[ajbura]

linux/arm/v7 is also requested in issue #489, is it possible to build that also?

[kfiven]

No, we have a dependency that needs a library that is not available on arm/v7 yet https://github.com/kfiven/cinny/runs/6072704815?check_suite_focus=true#step:7:565

 > [linux/arm/v7 builder 4/6] RUN npm ci:
#31 421.6 npm ERR! code 1
#31 421.6 npm ERR! path /src/node_modules/sharp
#31 421.6 npm ERR! command failed
#31 421.6 npm ERR! command sh -c (node install/libvips && node install/dll-copy && prebuild-install) || (node install/can-compile && node-gyp rebuild && node install/dll-copy)
#31 421.6 npm ERR! sharp: Downloading https://github.com/lovell/sharp-libvips/releases/download/v8.10.6/libvips-8.10.6-linuxmusl-armv7.tar.br
#31 421.6 npm ERR! sharp: Please see https://sharp.pixelplumbing.com/install for required dependencies
#31 421.6 npm ERR! sharp: Installation error: Prebuilt libvips 8.10.6 binaries are not yet available for linuxmusl-armv7