Add a release for linux/arm64

[nblack-er]

What would you like to be added:

Now that grype has an arm64 binary, it would be great if syft also had an arm64 version:
anchore/grype#362

Why is this needed:

This will allow software bill of materials to be collected for arm based environments.

Additional context:

[luhring]

Definitely! @spiffcs can you look at this when you get a chance?

[spiffcs]

I'll do a syft release today - we merged in #591 the other day so we should be able to produce this for syft.

[spiffcs]

Ideally, we can cut a release after the following are merged:

• Add SPDX JSON format object #584
• Port cyclonedx presenter to format object #589
• Update package identifier to be constant across multiple syft run #595

[spiffcs]

Follow up - it might be difficult to get all these in before a new release so we've started to process of cutting v0.28.0 so we can get support for arm64 out asap

[nblack-er]

Thank you very much for adding arm64 support in v0.28.0!