ci: switch PyPI publish to trusted publishing (OIDC)

[skuenzli]

Summary

Switches cedarpy's PyPI publish step from a long-lived API token to PyPI's Trusted Publishing (OIDC). Aligns with our supply-chain hardening work; the PYPI_API_TOKEN secret has already been deleted.

Changes in .github/workflows/CI.yml

• Remove env: MATURIN_PYPI_TOKEN: ${{ secrets.PYPI_API_TOKEN }} from the Publish to PyPI step — PyO3/maturin-action@v1 auto-detects OIDC when id-token: write is present and no token env is set
• Add environment: pypi to the release job so it runs in a protected GitHub environment, which:
  • Narrows the OIDC claim so other workflows/branches cannot mint a release token
  • Enables deployment protection rules (manual approval, tag-pattern restrictions, reviewer list)

id-token: write was already present (used for build provenance) and now also covers PyPI publishing.

Prerequisites (must be done before the next v* tag push)

These are manual user actions — this PR only stages the workflow side.

1. Configure PyPI trusted publisher

At https://pypi.org/manage/project/cedarpy/settings/publishing/ add a publisher with:

• PyPI project name: cedarpy
• Owner: k9securityio
• Repository name: cedar-py
• Workflow name: CI.yml
• Environment name: pypi

2. Create the pypi GitHub environment

In repo Settings → Environments → New environment:

• Name: pypi
• Deployment branches and tags: restrict to tags matching v*
• Required reviewers: add yourself (recommended — gives a manual approval gate before each release)

Why this is safer than a PyPI API token

• No long-lived secret to steal
• OIDC tokens are minted per-run, expire in minutes
• Environment + tag-pattern rule means a compromised feature branch cannot publish
• Optional manual approval gate adds a human checkpoint

Test plan

• PR merges, CI green on PR (no release step runs on PR)
• After merge, push a test tag (or use the v4.8.1 release) and verify the release job waits for environment approval, then publishes successfully via OIDC
• Confirm new wheels appear on PyPI with provenance attestations

🤖 Generated with Claude Code