Run CI on Node 22

[Socialpranker]

CI has been red on every PR for a while now, and it isn't the PRs. The "Make a small babel app" step runs create-react-app, whose template depends on @testing-library/jest-dom at ^6.9.1. That range now resolves to 6.10.0, which declares engines.node: ">=22", and the workflow pins Node 20, so yarn bails out before Danger ever runs:

error @testing-library/jest-dom@6.10.0: The engine "node" is incompatible with this module. Expected version ">=22". Got "20.20.2"

The same failure shows up on #1524 (22 Jul) and on my #1525, which touch unrelated things, so it's the workflow rather than either change.

This bumps node-version in CI.yml from 20 to 22, the minimum that satisfies the new constraint.

I left the rest alone deliberately. release.yml also pins Node 20, but it never builds a CRA so it isn't affected, and I'd rather not touch the publishing path without a reason. engines in package.json still says >=18, which is about what Danger supports for its users and is a separate question from what CI runs on.

One caveat on verification: I couldn't reproduce the failure locally, because a local create-react-app run resolved jest-dom to 6.9.1 rather than 6.10.0, and 6.9.1 still allows Node 14. So my evidence is the CI logs plus the published engines field on 6.10.0, not a local repro. The run on this PR is the real test.

#trivial

Written with Claude Code (Claude Opus 5); I reviewed and tested everything before submitting.

[Socialpranker]

CI is green on this one, so the local repro caveat above is moot now. The runner picked up node: v22.23.1, the engine error is gone, and the "Make a small babel app" step ran all the way through to Danger reporting both expected warnings:

Danger: ✓ found only warnings, not failing the build
Expect 2 warnings
the other

That's the step that had been failing, so this should unblock #1524, #1525 and anything else opened against main.

[orta]

👍🏻