Programmatically acquire release asset URLs in `phylum-init`

[maxrake]

Description

Use the GitHub API ("https://api.github.com/") to more programmatically get the archive URL in the phylum-init script.

Additional Details

It's statically coded right now and, while it works, may not always be the correct download URL for the release assets.

Acceptance Criteria

• The download URLs for the release assets of the desired version are acquired via API calls