Add an arm64 architecture variant of the Linux build

[mmizutani]

This PR adds an arm64 CPU architecture variant of the Linux build as a release target in addition to the existing amd64 (x86_64) Linux build.

Currently, unlike tbls-build, the release builds of the tbls program for macOS are available for both the amd64 and arm64 architectures to support both Intel CPU and Apple CPU, but the release builds for Linux OSes are only available for the amd64 architecture.

There are a couple of use cases where the arm64 arch Linux release of the tbls program is valuable:

• Installing tbls in a Linux OS container on an Apple CPU macOS machines without resorting to compatibility mode (enabling emulation of the linux/amd64 platform), which could hurt performance and development productivity.
• Installing tbls on Raspberry Pi devices, which are powered by ARM processors. This is armhf arch, not arm64.
• Installing tbls in workloads (e.g., self-hosted CI/CD pipelines) running on virtual machines and cloud container platforms powered by the AWS Graviton CPU, which is based on the ARM CPU architecture.

[k1LoW]

@mmizutani Thank you.

tbls uses Cgo and requires additional maintenance to get Linux arm64 builds onto the release pipeline.

We have added a test for the release pipeline and hope you will check it out.

[mmizutani]

Thanks for preparing the release-test CI workflow.

The linux-release-test Job has successfully passed, but my unnecessary change unrelated to this PR caused the darwin-release-test Job to fail.

Now that the unnecessary commit has been dropped, all the jobs in the next CI run would pass.

[k1LoW]

@mmizutani GREAT WORK!!!! Thank you!!!!!

[mmizutani]

Thank you for the review and for the awesome CLI program!