Run CI on more different architectures in some more systematic manner

[Jakuje]

Currently, the CI runs only on amd64. The #283 added i386 builds (on amd64 cpus). Github provides also arm64 runners which might be interested.

https://docs.github.com/en/actions/using-github-hosted-runners/using-github-hosted-runners/about-github-hosted-runners#standard-github-hosted-runners-for-public-repositories

Originally posted by @Jakuje in #282