copy github workflow from syntax/

Author: kevinbarabash

.github/workflows/ci.yml

@@ -0,0 +1,38 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  test-syntax:
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/[email protected]
+
+    - name: Cache OCaml's opam
+      uses: actions/[email protected]
+      with:
+        path: ~/.opam
+        key: macos-latest-ocaml-4.06.1
+
+    - name: Use OCaml
+      uses: ocaml/setup-ocaml@v1
+      with:
+        ocaml-version: 4.06.1
+
+    - name: Use Node.js
+      uses: actions/[email protected]
+      with:
+        node-version: 14.4.0
+
+    - name: Install depedencies
+      working-directory: ./syntax
+      run: npm ci
+
+    - name: Run tests
+      working-directory: ./syntax
+      run: eval $(opam env) && make roundtrip-test