Modernize dev tooling (uv, Ruff, Pyrefly, pydantic v2, click 8, GH Actions)

[giancarlosisasi]

Summary

Follow-up to #14

This PR modernizes danger-python's development toolchain and runtime dependencies, replacing the 2019-era stack (Poetry, black, isort, flake8, pylint, mypy, Travis) with current tools. What Danger does is unchanged; the goal is just to make the project easier to build, lint, type-check and test on modern Python.

Compatibility note: the package is still pre-1.0 (this bumps it to 0.2.0), so these changes fall within what semver allows for a 0.x release. The two things worth flagging are that the minimum Python is now 3.13, and the runtime deps move to pydantic v2 and click 8. Happy to adjust the Python floor if you'd prefer a gentler baseline.

Toolchain changes

Concern	Before	After
Env / deps / lockfile	Poetry	uv (uv.lock)
Lint + format	black, isort, flake8, pylint	Ruff
Type checking	mypy	Pyrefly
Python baseline	3.7	>=3.13
Runtime deps	pydantic v1, click 7	pydantic v2, click 8
CI	Travis	GitHub Actions (3.13 / 3.14 matrix)
Config home	setup.cfg	pyproject.toml only

What is preserved

• The 100% coverage gate. pyproject.toml keeps fail_under = 100 under [tool.coverage.report], so the suite still fails below full coverage.
• The danger-js input/output JSON contract. The JSON fixtures under tests/fixtures/ are untouched. The only fixture edits are typing cleanups in the .py helpers (Dict[str, Any] becomes list[str], Optional[str] becomes str | None).
• Public behavior and the danger-js shell-out flow.

CI

Adds .github/workflows/ci.yml with two jobs, both installing via uv sync --frozen: a quality job that runs ruff format --check, ruff check, and pyrefly check on Python 3.14, and a test job that runs pytest with the coverage gate across a 3.13 / 3.14 matrix. It also adds a new action.yml, updates the Dockerfile, and bumps actions/checkout to v4 in the existing danger.yml.

Notes for reviewers

Given the size, I'm happy to split this into smaller, independently reviewable PRs (uv, then Ruff, then Pyrefly, then pydantic v2, then click 8, then CI) if that's easier to review. I can also raise or lower the minimum Python version if a less aggressive baseline works better for you.

[giancarlosisasi]

Hi @orta , there is the MR 🚀

I have two questions:

• I think the next change could be to release this (I need to set up that action). I think it should be a separate MR.
• After checking the code, I can see it depends on Node.js and danger-js. Is there a possibility that we could implement all those features natively here in Python? (lot of work, but I think it's possible)

THanks!