Add 'test' github workflow (#10)

Author: zachkirsch

.github/workflows/test.yml

@@ -0,0 +1,30 @@
+name: Test
+
+on:
+  push: { branches: ["main"] }
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v3
+
+      - name: Install pnpm
+        run: npm install -g pnpm
+
+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Test
+        run: pnpm test