Add native support for ARM64 Docker containers

[enocom]

The latest release's tagged containers don't support ARM64 architectures, but should (as they have in previous releases). This is a regression in our release pipeline and will be fixed ASAP.

Meanwhile, anyone looking for an ARM64 container may use v1.13.5 which still supports both AMD64 and ARM64.

[enocom]

Lowering the priority as current versions of Docker will still run the container through virtualization while logging an warning.

[enocom]

Converting to a feature request given we're spread thin and won't have time to get to this, unless we hear from the community that this is actually useful or necessary.