chore: bump version to 0.20.0

[lambdalisue]

Summary

• Update version to 0.20.0 in deno.json
• Update deno.lock to reflect new version
• Update flake.lock with latest dependencies

Test plan

• CI checks pass (verify, scenario-test, scenario-test-nix)
• Ready to merge and trigger publish workflow

[Copilot]

Pull request overview

This PR bumps the version of @probitas/probitas from 0.19.1 to 0.20.0 and updates the Nix flake dependencies. The version follows semantic versioning with a minor version increment.

Changes:

• Version updated from 0.19.1 to 0.20.0 in deno.json
• Nix flake dependencies updated to newer nixpkgs revision

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated no comments.

File	Description
deno.json	Updates package version from 0.19.1 to 0.20.0
flake.lock	Updates nixpkgs dependency to newer revision with updated hash

Note: The PR description mentions updating deno.lock, but no changes to deno.lock are shown in the diff. This may indicate that either the file wasn't modified, or the changes weren't included in this review.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.