CI: build & publish linux/arm64 images

[derhuerst]

remotely related: #249

This PR configures Jib to build linux/arm64 images, so one can run them natively on ARM machines, as documented here.

[testower]

Can you provide some context please :)

[derhuerst]

Can you provide some context please :)

Sure! I have edited the PR's description.

[testower]

Are you going to run lamassu on ARM architecture?

[derhuerst]

Are you going to run lamassu on ARM architecture?

Yes. Both in dev (locally, Apple Silicon) as well as in production (on my ARM64 VPS, which is noticeably cheaper than x86).

[testower]

Ok you need to resolve the conflict in pom.xml, since it now has the from image defined.

[testower]

There's also this:

Error:  Failed to execute goal com.google.cloud.tools:jib-maven-plugin:3.3.2:dockerBuild (default-cli) on project lamassu: multi-platform image building not supported when pushing to Docker engine -> [Help 1]

[derhuerst]

Error:  Failed to execute goal com.google.cloud.tools:jib-maven-plugin:3.3.2:dockerBuild (default-cli) on project lamassu: multi-platform image building not supported when pushing to Docker engine -> [Help 1]

dockerBuild will fail because – apparently, no sure why – Docker doesn't support building for non-native and/or multiple platforms. build, as executed in the CI, does work though for me though.