Add GHA workflow for ruff

.github/workflows/main.yml

@@ -0,0 +1,17 @@
+name: ruff lint
+
+on:
+  push:
+    branches:
+      - 'master'
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+
+jobs:
+  run:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: jpetrucciani/ruff-check@0.1.0
+        with:
+          path: reference