add: github workflow

.github/workflows/build.yml

@@ -0,0 +1,20 @@
+on:
+  - pull_request
+  - push
+
+jobs:
+  build:
+    name: Test Build
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: install node v12
+      uses: actions/setup-node@v1
+      with:
+        node-version: 12
+    - name: yarn install
+      run: yarn install
+    - name: Build
+      run: yarn build
+      env:
+        CI: false