Migrate to GitHub Actions

.github/workflows/workflow.yml

@@ -0,0 +1,37 @@
+name: Main workflow
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        os: [macos-latest, ubuntu-latest]
+        node-version: [8.x]
+
+    runs-on: ${{ matrix.os }}
+
+    env:
+      BS_TRAVIS_CI: 1
+      OCAMLRUNPARAM: b
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Checkout submodules
+        run: |
+          auth_header="$(git config --local --get http.https://github.com/.extraheader)"
+          git submodule sync --recursive
+          git -c "http.extraheader=$auth_header" -c protocol.version=2 submodule update --init --force --recursive --depth=1
+
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Install packages
+        run: npm ci
+
+      - name: Run tests
+        run: npm test