Downloading such assets is preferable since:
- they contain updated metadata (useful for debugging)
- they contain only the production files
- they are pre-built: GitHub doesn't have to create a ZIP from a tag
- Always specify the PHP install dir
- Use default PhpManager functions
- Fix CA Authorities (so that HTTPS calls work)
- Don't handle the special xdebug case (it's bundled in PhpManager)