Add lint workflow

.github/workflows/lint.yml

@@ -0,0 +1,18 @@
+name: "Lint"
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup tools
+        run: scripts/devsetup
+      - name: Run linter
+        run: gdformat .