Add Github workflow for CI tests

.github/workflows/validate.yml

@@ -0,0 +1,17 @@
+name: validate
+on:
+- push
+- pull_request
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version:
+        - 12
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: make validate.ci