feat: support more Zig SDK versions

[aherrmann]

Add a script to generate the set of known versions to prepare for future automation.
Read the URL and SHA from the generated data to be more future proof.
Add integration tests to test for all supported Zig SDK versions.

In preparation for #72.

• script to generate versions file
• sort versions according to semver
• Add a Bazel target to update Zig versions
• Update Zig versions
• Update the known platforms
• Read URL from versions file
• remove outdated todo note
• Factor out the integration test helper
• Test all Zig versions in integration tests.
• Use the latest Zig version for testing.
• fmt