actions: Add build and lint

Closes #512

.github/workflows/ci.yml

@@ -0,0 +1,18 @@
+name: Build and Lint
+
+on:
+  pull_request:
+  push:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2.3.4
+      - name: Setup Node.js
+        uses: actions/setup-node@v2.4.1
+        with:
+          cache: "yarn"
+      - run: yarn install --prefer-offline
+      - run: yarn build
+      - run: yarn lint --no-fix