Move to GitHub Actions for CI

.github/workflows/ci.yml

@@ -0,0 +1,15 @@
+name: Node.js CI
+
+on: push
+
+jobs:
+  format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Use Node.js 18
+        uses: actions/setup-node@v3
+        with:
+          node-version: 18
+      - run: npm clean-install
+      - run: npm test

.travis.yml

@@ -1,6 +0,0 @@
-language: node_js
-node_js: 'stable'
-script: npm test
-notifications:
-  email:
-    on_success: never