Closes Dependabot PR #2.
v3 changelog: adds an optional commit-message parameter (we do not
use it, default is fine), removes the Endbug dependency that caused
issues on github-enterprise, and bumps its own internal checkout /
setup-python actions. None of the inputs we pass (lint-path,
python-version, requirements-path, pylintrc-path, readme-path,
badge-text, color-*) changed.
Re-pinned by full commit SHA, same hardening pattern as v2.1.
Richard Nixon
4d16704ede