Migrate CI from Travis to GitHub Actions

* Travis CI stopped running after the free open-source plan was
  discontinued, so `master` and pull requests had no CI.
* Add a GitHub Actions workflow running `make setup` and `make test`
  on ubuntu-latest and macos-latest.
* Swap the dead Travis badge for the Actions badge and remove
  `.travis.yml`.

Author: tommarshall

.github/workflows/ci.yml

@@ -0,0 +1,21 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install test dependencies
+        run: make setup
+      - name: Run tests
+        run: make test

.travis.yml

@@ -10,6 +10,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 
 * Document installing globally via `core.hooksPath`.
 
+### Changed
+
+* Move continuous integration from Travis CI to GitHub Actions.
+
 ## [v0.7.0] - 2026-08-26
 
 ### Added

CHANGELOG.md

@@ -1,6 +1,6 @@
 # git-good-commit
 
-[![Build Status](https://travis-ci.org/tommarshall/git-good-commit.svg?branch=master)](https://travis-ci.org/tommarshall/git-good-commit)
+[![CI](https://github.com/tommarshall/git-good-commit/actions/workflows/ci.yml/badge.svg)](https://github.com/tommarshall/git-good-commit/actions/workflows/ci.yml)
 
 Git hook to help you write good commit messages.